This looks on the surface to be more file-corruption than virus related. That said, viruses can corrupt files, so I wouldn't completely rule it out. Intermittent issues like this are particularly tricky to track down, IME.
What does the "white writing" say?
Are there any clues in your bootlog.txt file?
To overcome file corruption, boot up, run scandisk, and defrag your hard disk(s). This will help 90% of the time.
If you're running low on disk space (less than 10% free), then clear up some space. If you've got more than 40 files in your root directory, remove as many as you safely can.
Clear down *.tmp files from temp, windows, windows\temp and other temporary areas. Search for files with a *.tmp extension and delete those suckers. Do the same for files that begin with a ~.
THEN run a virus checker.
Maybe the swap file is fragmented.
It can be rebuilt by either deleting it (the old hacks way), or setting it to 0 in the Virtual Memory options, then rebooting and setting it back to the size it originally was (then rebooting again!).
If you're still having issues, maybe it's time for a rebuild - while you can still access the PC to back up your precious data!
Troubleshooting Microsoft = The 3 R's; Reboot, Rethink, Rebuild.
Hope this helps