x64 boot problems

Hi,
Ever since I installed vista home premium x64 on a fresh pc I have been experiencing major issues with it that have rendered the computer barely useable. Sometimes it works fine, but the main problem is that 3 out of 4 times, I cannot succesfully boot to the desktop.

The main problem I have is that whenever I boot, I get a message saying 'Windows has failed to start'. When I try to go ahead and instruct windows to start as normal, it gets a BSOD and reboots. The only way I can fix this is by booting off my installation disc and getting startup repair to do a system restore. After this windows will start succesfully once, and after that the same problem recurs.

Another problem is that when windows boots I often just get a black screen with a cursor, just before the blue windows logo is meant to show up. This screen will just stay there until I reboot.

Occasionaly Windows will boot ok but I will get messages saying that the userlogon UI process has failed.

Often I can boot and logon, but then Windows forces me to try and activate. I can't. I've tried phone, internet, and re-entering my product key, but I can't get it to work. Sometimes I will get errors along the lines of 'There has been an error in the product activation store'.

I have also experienced windows explorer crashing frequently, along with random app crashes. I have had a few random BSODs.

Specs:
CPU: E8400
Mobo: GA-G33M-S2L
VGA: Asus 8600GT
RAM: Apacer 2GB DDR2
HDD: WD Cavair 500GB

Vista home prem x64 OEM SP1 (It's a genuine copy btw)

I know that the advice I am likely to get is that I should update every driver. It is a nightmare for me to get all of the drivers I need on dial up, (as well as all of the patches I need for my programs. I have managed to obtain SP1 and the latest NVIDA drivers, although I am still trying to install the latter, (as I have to reboot to complete the installation, but when I reboot windows will not start, and I have to system restore, undoing the installation). I am not really sure what drivers I need, because the only ones I have installed are graphics and modem. Everything else has been plug and play. I have removed the modem, and I am going to uninstall the software as soon as I can get my computer to work, as I'm not using it, and its a crappy generic model, and apparently bad drivers could be causing my problems.

Go into the event viewer. Right click on each category and clear them. Reboot. This will give you only the errors from the restart. Post the first error. Did you run chkdsk c:/r from command prompt. Right click on command prompt in accessories and run as administrator. Then type chkdsk c:/r. I would also recommend running the manufacturer's disk utilities to see if you have a bad hard drive. Did you apply all the chipset patches for Vista. Check your device manager for items not installed properly.

I have discovered that my pc will consistently boot in safe mode. I have installed a chipset update from intel, which has made no difference.

I entered the checkdisk command, but it wouldn't work, although it said chechdisk was scheduleded to run at the next reboot (which it didn't). A few days ago the computer wanted to check the disks whenever I booted, and it didn't find any problems, so I guess this means my HDD is fine?

When I went into event viewer, it crashed, saying something about MMC failing.

I went into device manager and found the only part which wasn't functioning, which I disabled. (This has made no difference).

I should also mention that I have experienced problems with graphics, which I put down to old drivers, but the latest graphics drivers haven't fixed it.