My computer was running fine a few days ago. Today I was going to log into my account in the login screen,it was working fine. The windows load the wallpaper but it just logs me off automatically. The icons and start menu does not load. I don't have a chance to figure out the problem because it does not allow me to log in. I'd be happy to take any advice to solve this problem

Same in Safe Mode?

Yes I tried safemode. The computer just won't log in

If you have Vista DVD...

Repair Install For Vista - Vista Forums

If you don't have Vista DVD...

1. Create Vista Recovery Disc.

Option 1:
http://www.c4consulting.com.au/soluc...SOLUCTIONS.htm

Option 2:
Download Vista Recovery Disc iso image: Windows Vista Recovery Disc Download — The NeoSmart Files
Burn it to CD, or DVD: Burning ISO Images to a CD or DVD - NeoSmart Technologies Wiki

2. Boot from created disk.
At first screen click on Repair your computer:

This will bring you to a new screen where the repair process will look for all Windows Vista installations on your computer. When done you will be presented with the System Recovery Options dialog box:

After this, it will present you with a list of options including startup repair, system restore and command prompt:

Try System Restore, first.
If that doesn't work, try Startup Repair.