lots of problems- now Vista won't boot from CD

I have a NVIDIA GeForce GTS 250 Graphics card, Vista Home Premium 64bit.

A few days ago, when booting up my PC, I noticed my display properties- Aero, etc.- were not loading. I checked Device Manager to see what was going on with my video card and saw an error message: Windows cannot initialize the device driver
for this hardware (Code 37). I tried checking for updated drivers (none), rolling back the driver, uninstalling and scanning for hardware changes then reinstalling the video card. Nothing worked. Google lead me to a suggestion to run sfc /scannow. It got 41% through the verification phase and quits, both in regular and safe mode (even run as administrator).

The next day, Windows reported an update for my video card, so I tried to install it but it failed. Error code 80070490. This is the only update that won't work, several others were downloaded and installed at the same time with no problems.

Then I tried to restore to a point a few days ago, the graphics problem was not fixed, but the computer booted up fine. This morning, booting the computer it said that there was an error loading the operating system, so I put in my Vista CD figuring I would just do a clean reinstall. However, when booting from the CD, the white loading bar (it says Windows is loading information, or something similar) appears and finishes, then a black screen with the word Windows & a green loading bar for a minute, then it just goes to a black screen and stops. Even after an hour, it doesn't go past the black screen.

At this point I have no idea what to think- what is going on with this computer? It's a self-built computer, only a couple months old. Is this a graphics card issue or a corrupted hard drive or what?

I did some more googling and found a suggestion to download some diagnostic software from the drive manufacturer. Ran the diagnostic and halfway through it stopped, saying too many errors were found to repair. RMA'ing it tomorrow.

I feel stupid, but I didn't know about the diagnostic software. So just thought I'd post in case someone else has a similar set of problems and this might help them.

Regarding the boot from CD - if you want to do a clean install, at least from my experience, it can't be done by booting from disc. I used an anytime upgrade disc (which is supposed to be just a regular Vista disc), and instead of "upgrading", I just installed over the current operating system (which also happened to be Vista, hence a clean install).

Do you know if there's any software that might have corrupted system files? Or that made a mess somewhere else? At this point, it looks like a clean install will do good for your system - that's what I would do. Keep this thread updated! :D