Explorer.exe Constantly Freezing/Crashing When Modifying Files or Browsing

Type of Operating System: Windows XP SP2 (fully updated with patches)
Browser Used: FireFox 2.0.0.16 (updated)
Age of PC: Less than 6 months
Problem occurs when: Modifying files (usually exe files but also with other shortcuts and files), sometimes when browsing
Error: explorer.exe usually crashes and restarts; sometimes the errors below.
The instruction at "0x7c911f2" referenced memory at "0x006f006a ". The memory could not be "read ".
Cannot read from source file or disk

Hi, for some reason whenever I am examining files (usually right clicking and then clicking delete or properties, but also when browsing), explorer.exe crashes on me and restarts. I have no idea what could have caused this to occur. I do know that a couple instances of drwtsn.exe pop up in task manager along with imapi.exe sometimes following a crash. Sometimes instead of explorer.exe restarting, it simply freezes until I 'end process' dr.wtsn.exe, after which, explorer restarts. Some files are perfectly ok for me to check its properties or delete (usually zip files, pictures seem ok, etc.), but other files bug out on me for no reason. I have checked files in various locations of my harddrive, but still notice the problem.

So far I have not encountered any problems browsing the web or using programs. It's only when I browse explorer or right click some files.

I have tried another malware support forum already, but they were unable to determine the problem after a series of diagnostics. The link is here: http://forums.whatthetech.com/Explorer_exe...752#entry480752
I am currently trying their Windows support section.

As the link shows, I have run a number of anti-spyware and anti-virus scans, but have found nothing that would determine the cause of the problem. I've done a sfc /scannow command to verify windows integrity of files, but to no avail.

I have run memtest overnight with 0 errors.

I would like to note that the problem did seem to be fixed once when I used 'ATF_Cleaner' that deletes all temp files from your PC. I'm fairly certain that I was able to examine all files without a problem, but a few hours later, I noticed that it started again.

I disabled drwtsn.exe from the GUI if you run it start->run... I unchecked everything from options. This didn't seem to fix the problem though. I did once try and delete drwtsn.exe from the registry manually, but I can't remember if that was before or after the problem. I restored the registry changes anyway.

UPDATE: Just noticed that dr.wtsn.exe still runs in my task manager. That's wierd.

NOTE: I am submitting my problem to multiple help sites in order to obtain any suggestions whatsoever as to what could be causing this. I hope this is ok, but I want to do the most I can before I even think about reformatting (which may not fix the problem if it's on my storage partition)

Any help would be greatly appreciated. Thanks.