I've just reloaded a PC from scratch (wiped drive) with Win2000. Afterwards, I loaded the drivers, and then finally, performed Windows Updates (IE 6.0 SP1, Win SP4, Ect.). Now, I cannot view JPEG's in Internet Explorer or Windows Explorer. Other applications can view jpegs, and the problem is not effecting GIF's. The images show up as a purple scrambled block. Any ideas??

I've seen a similar problem before and I suspect there is a registry file association problem with the .jpg format.

Microsoft support page: Q192573

There is a note at the bottom of the Microsoft page that may be relevant:
NOTE: This issue has been know to occur after an installation of Internet Explorer 5.5 SP1. This was resolved by running the Internet Explorer Repair Tool.

Trouble with graphic file associations

I hope this is of some help!