Xpert98, can't view JPG or MPG with IE4 or 5...

(using driver 2560)
...but I can view JPGs with Netscape, and MPG files with the ATI Video Player.
JPGs appear all screwed up under IE4-5, can't even describe it. MPGs have green blocks and lines when using Windows Media Player, but don't when using ATI Video Player.
I have e-mailed ATI Tech support monkeys about this, and they can't figure it out.
And Microsoft says that I should e-mail ATI about it. What gives?