Multiple Issues with Vista x64, any help appreciated

Sorry for the length of this post, but I'm not sure what info is relevant, and what isn't, so I tried to group it properly. I apologize if this is in the wrong place, or wrong format, or if I didn't include necessary information. Any and all help is appreciated.

I have a lot of back story here, so I'll summarize my current issues at the top, here:
- System Event Viewer gets an "MMC could not create the snap-in" error (also applies to other snap-in modules, but many still work)
- .NET 3.5 SP1 will not reinstall (installer quits with error code 1603)
- Windows installer 3.1 setup gets "Not enough storage is available to process this command" error
- Sun VirtualBox no longer starts (get a side-by-side configuration error)
- VMWare Player no longer opens virtual machines (either permissions error or W32AuthConnectionLaunch error)

Info directly related to these errors that I believe is relevant:
- The Event Viewer error resulted in a CLSID: FX: <what looked like a registry key>. I searched the registry for this, and it came up with an entry in "HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>MMC>SnapIns"...which makes sense. All of the keys in here that are prefixed with "FX:" get the same error when I try to add them to a blank MMC window, while all the other Snap Ins in that tree are fine.

-I've tried resetting the registry permissions as seen here:
Having trouble installing the Vista SP1 update? Reset your registry permissions! - Aaron Tiensivu's Blog
-I've tried uninstalling/reinstalling all programs that get the errors.
-I've tried all steps here:
MMC fails to load event viewer in RTM : Windows Vista Announcements : Windows Vista IT Pro : Microsoft TechNet Forums
-I've tried removing .NET completely with this:
Aaron Stebner's WebLog : Removal tool to fix .NET Framework install failures
-I've tried most steps in the "Repair Vista Options" tutorial on this site:
http://www.vistax64.com/tutorials/101393-repair-vista-options-preferred-sequence.html
- the system file check results in corrupted files that cannot be repaired, but trying to install the Automated Installation Kit fails, stating "WinPE.cab" is not found

It seems like all of these different errors might be related, so I'm hoping someone might recognize some common thread between all of these things that I can't grasp. I really want to avoid a complete restore, if possible, but I understand if it's necessary. Unfortunately I only have the ASUS recovery CDs for Vista, not an original install cd, so I can't do the Repair option, as far as I know.



Now for the back story of it all...

I recently purchased an ASUS G50VT-X6. In general I've been very pleased with Vista.

I uninstalled the Norton trial version that came with the laptop, and went through the process to attempt to install AVG (free version). After lots of trouble with that never activating the "Resident Shield", I decided to try Avira Antivir Personal, which installed with no issues.

Somehow, along the line, I have mucked up some part of my Vista configuration. I started with investigating the issues surrounding the two virtual machine programs not running. This led to realizing the Event Viewer had the issue it had, which led to attempting to reinstall .NET, which led to trying to reinstall the Windows Installer 3.1.

Each step of the way seems to have uncovered more errors, as listed above. One suspicion I have is when I was using CCleaner to try to help with the AVG reinstall, and I cleaned the registry possibly unnecessarily, or removed something important. Although backups were created, which I attempted to reinstate, also to no avail.

Anyway, as I said, any and all help is appreciated. Thanks in advance.

- James

Kudos on the problem description. It's well-written and unemotional, as it should be.

My gut feeling is that you won't find a single root cause for all of this, but at least the installer error and the .Net issue are probably linked.

As a suggestion, try bumping up the IRPStackSize as per:

Description of the IRPStackSize parameter in Windows 2000, in Windows XP, and in Windows Server 2003

The "not enough storage" error actually suggests that you've got too many drivers competing for space in a kernel-mode work item called an IRP ("I/O Request Packet", no direct link to networking). That IRPStackSize parameter governs the size of each IRP, so if you bump up the number from the default 25 (on Vista) to say 32 (decimal), and then restart the box, you might see better results. Otherwise, undo the change because bigger IRPs consume some very precious system resources.

Also, I'd suggest throwing out all registry "cleaners". Those utilities are snake oil - they cannot possibly repair problems of this nature, unless their cumulative damage leads you to just reinstall the entire box from scratch