Slow start and buggy performance with Windows Vista Ultimate 32 bit

Hello,

I am at a loss as to what is wrong with my personal PC. I have been running Vista for 3 years with no problems.  The only I had in these 3 years is would occaisionally not detect my DVD drive.

Around the beginning of December it started to act a bit strange.  Coincidentally, it seems to have started when I installed whatever windows updates were available at the time. Here is a list of it's symptoms in the past month:

1. When taken out of sleep mode I have gotten a blue screen about 3 times
2. The start-up of windows has become painfully slow. Once even taking 45minutes to get to the sign-on screen.  This is every time I start my machine.
3. On a few occasions windows fails to start and I had to dig up my installation disc to even boot.

My steps to cure this started w/ doings some thorough virus scanning, even though I had a pretty liable program in Avast for some time now.  I also attempted to restore my PC to an earlier date, and now it seems to be slower and hung up in a loop about windows updates. Every time I restart/shutdown I get the Vista screen that says it's installing/initializing updates.  This can't be the case - but none have been downloaded.  This happens on every restart/shutdown.

Ever since I restored, I also can't get windows update to work. It shows me updates, but none will download. I went to the support website and downloaded them manually, but the standalone installer won't work either. It just churns and churns...

Also, since the restore, I can't uninstall any of my programs. I barely have any programs as it is, but I was just trying to create as clean as slate as possible during this troubleshooting, but I can't. It just does nothing.  

I have downloaded and installed a new antivirus (AVG) just to be extra thorough and it shows nothing is wrong.

This leaves me with something is buggy with windows, my registry, or some other sort of conflict.

As for windows update in general - it had never prompted me to download SP1, so I didn't know it existed. Not until I received the first blue screen a little of the month ago did I get a windows suggestion to download it. Of course, I can't install it. I have it downloaded on my desktop manually (the huge 435MB file), but can only look at the pretty icon.

SIGH

Any ideas or suggestions?

Thank you in advance!