black screen after log in and other problems

Hello I am posting because my pc recently developed a bunch of problems. Usually I can figure stuff out on my own but with this I'm just out of my element.

Heres a quick summary: On the morning of April 16th my mom was on her account and everything was fine. Later I had got on my account and spent the entire day trying to get a program I had bought to work correctly. (PowerDirector10Ultra video editor) After installing certain programs/updates it needed to run properly and making some changes the program worked fine. It wasn't until when my mom tried to log on her account that night we discovered some problems. Now during the day I saw a few things that were different on my account but didn't think they were "problems" at the time but now I know something is not right.

Now I will be honest, I made a change to my computers registry but I only changed one thing,I didn't touch anything else and I exported the registry before doing anything(you can read what registry change I made down In my full summary)I am starting to think that its all a coincidence and I'm sure that its something having to do with vista that's causing this. I have never liked it and in the past updates have caused major unexplainable problems before. What I will do is list my problems along with any info I feel everyone needs to know to help me out. After that I will post a summary of what I remember doing when I was trying to get my video editing software to work.

My problems as of now I have found are:

-All accounts except for my account get a black screen after log in,during the black screen task manager works but I cant run explorer.exe(my account is administrator,and so is my mothers,but her account is one of the accounts that get the black screen)

-Red x on network status icon.Network status:unknown,server execution failed.My network and all I fine. I can get online with no problems.

-All windows look different now,dell dock on desktop appears at the top of the screen when I have always had it disabled. Some windows like when uninstalling prgram appear as plain white a blue format.Like its from the 90's(I know theres a word for it...)

-When in safe mode I cant execute certain services because of privileges and what not.

-Windows Explorer has stopped responding a couple of times. It has happend once on my account(the one that works) and It happens mostly when I am In safe mode.(I cant make it to the add/remove program because windows explorer crashes and then restarts)

Okay heres the full summary of what changes I have made from the beginning.

1. Installed PowerDirector 10 Ultra-(requires quicktime,if not PowerDirector 10 projects wont play,laggy,software freezes/crashes when editing,audio will play but video doesn't play smoothly/at all,program crashes)

2. Attempted to Install Quicktime-Got this error during installation:

"Quicktime for Windows:There is a problem with this windows installer package. A program required for this install could not be run. Contact your support personnel or package vendor."

After clicking "OK" quicktime would be installed but the install would be broken. Upon trying to uninstall the broken quicktime I got this message with a red X

"Windows Installer:The Windows installer service could not be accessed. This can occur if the Windows Installer is not correctly installed. Contact your support personnel for assistance."

Even though I got the error quicktime would still uninstall. I also Uninstalled PowerDirector10

I searched these errors in google and everything I seemed to read regarding this error pointed towards the Windows Installer files being corrupted. On a site I found a help section with a couple different methods about fixing a corrupted Windows installer. A lot of people posted saying it worked so I followed these steps

method #1.First I did did a system scan "sfc /scannow" in the command box I ran as administrator. When done it said there were some files that couldnt be repaired,then gave me the files path to the scan log.I can post this If needed/or perform a new one.

3. Attempted to install Quicktime again.No difference,still got the errors.

Method #2. I then checked to see if Windows installer was running in the services "services.msc",It was. I also made sure it was one of my start up programs and was set to "manual".

4.Installed Quicktime again.No difference,still got the errors.

Method #3. Typed "msiexec" In run to make sure I had Windows Installer 4.5. and I did.

5.Installed Quicktime again.No difference,still got the errors.

Method #4. Following a help guide on microsoft I Exported a copy of my registry to my desktop,then moved it to an sd card for safe keeping. Found Windows installer in the registry Msiexec.exe and changed the image path from what it was to

"C:\Windows\system32\Msiexec.exe"

After changing the path I restarted the computer In safe mode,opened the "run" module and re registered the "Msiexec.exe" file by running "msiexec /regserver". I did not modify any other file/path in the registry besides the windows installer.

At this point Is when I noticed windows defender icon popped up in the desktop tray. Upon maximizing It,It said the following was turned off:
Windows firewall
Windows Defender
Norton Anti Virus
Automatic updates

I clicked on Norton anti Virus and it said everything was secure. I tried turning windows fire wall on but Norton said that I didn't need to because It would interfere. I wanted automatic updates off because Updates that were download automatically before have caused problems. trying to turn windows defender on it tells me that is cant download something After hiding the Windows Defender alert I think I downloaded a dell related update that was available.

After this happend I had norton run a full system scan,I thought maybe this was a spyware "windows look-a-like" but everything checked out.

While this was all happening,my windows colors changed,also the dell dock for programs at the top of the screen was there,when I had it disabled prior.

7.Installed Quicktime again.No difference,still got the errors.

After doing all that I could with windows install. I found some forum articles about the Windows Installer problem when trying to install Quicktime,Bonjour,Itunes and apple updater/programs.

I went into my programs files and manually deleted quicktime,itunes,bonjour and other apple files that were there.

8.Installed Quicktime.quicktime installed fine.I then installed the rest fo the apple programs such as itunes,bonjour and apple updater.

9.Installed PowerDirector 10. Power Director10 worked fine.It didnt lag,freeze or crash.Everything was okay.Windows installer was working fine.



Hours later my mom gets on the computer. She clicks on her account to logon and after some unusual welcome screen loading time it goes to a black screen.(she was able to access her account that morning) I opened the task manager and saw that explorer.exe wasn't on there. I tried to run it but it would appear for a second then go back off. I tried to log on other accounts and had the same problem. I got on her account in safe mode and explorer.exe started.

Since I found this problem out I have:

-changed group policy settings.(under the user accounts I checked the boxes giving everyone permission but still had the black screen.)
-Turned off user account control
-I have uninstalled a lot of programs I thought may have interfered with computer files.(norton,aim,other not important stuff and even uninstalled the quicktime,itunes,bonjour,apple updater.i also went in and deleted what was left over after uninstall)
-I have also tried uninstalling updates that were downloaded.There is only 1 dell update for the 16th(day problem started) but theres no "uninstall"option when selected.
-I have tried numerous system restore.I tried to restore it to that morning before i was on,and i tried to ding it to the 15th and earlier and when i log back on it says system restore was not able to do a system restore.

Whether or not this was all caused from what I have done I am not sure. I cant remember what the windows installer path was originally before a changed it.Windows installer works fine so I don't know if I need to change it back or what. My mind is about toasted and I posted as much as I could remember of what I did. If the problems occurring are because of a change I have made or what not I will man up and admit I shouldn't have just looked my problem up online and followed instructions,even though the problem was explained to the 'T".

I have all my original pc startup discs and all. If it comes to it I will put all my personal files on card/cds and either try to do a complete reinstall of the operating system or take my pc some wheres and have someone do it for me.

My computer system is:

"Manufacturer:Dell
Model:Studio 540S
Processor: not available
memory:not available
System type: 64-bit Operating System"

The system card actually says "not available" so I dont know what that means.

Any other information please ask I will get it.

Run the free, bootable diagnostics from here: Initial Hardware Diagnostics
In particular, run at least one of the anti-malware tools (to ensure that your Norton hasn't been corrupted).
I suspect malware because of the behavior that you describe for explorer.exe (it comes on and then shuts down on it's own).

Create a new user account and see if that account works normally.
Backup all the user data for all profiles while you can still get into Windows.

Update all drivers and programs from the manufacturer's website (one of the most common causes for black screen errors).

Yes i tried creating a new account,made it an administrator account too and it still had a black screen when I signed in.

Right now Im in the middle of backing up all of my data.

Backing up is the best thing to do (IMO).
I've spent weeks trying to fix these things - only to resort to a format and reinstall in the end.

Update all programs and drivers to see if that will fix it.

Well I clean reinstall did the trick. Thankyou for your time and help.