You may have been hit w/malware fake windows update or,
One or more updates may not have been compatible.
Do this w/ power supply plugged in, don't run the battery down.
Turn all security and firewall OFF.
Start>All Programs>Accessories>System Tools>System Restore,
Then select a date (if system restore has one) to restore to, and follow through with the prompts.
This sets the hard drive back to a day (the day) before the problem occurred.
If system restore is not working a virus could have disabled it.
Normally, when Windows Update Installs updates, a restore point IS created.
Now follow thru:
The system was restored to a previous date > your documents are saved, etc...
Turn Firewall and security back ON.
OR
Malware may have and still is running...
OR
Incompatible legitimate update has corrupted something(?)
If system restore was able to recover the system, make backups of all your lost files, quickly.
Always make backups of your files...in case the system is corrupted.
Turn off automatic updates, so that the same update does not cause problems a second time.
(history can repeat itself)
Check the manufacturer(s) website for a list of incompatible updates.
All updates are not compatible with all hardware / drivers, etc...these kinds of glitches can occur.
I recommend:
Critical updates only, manually installed.
This way I avoid problems that could occur.