I have two PCs and one of them displayed this fault, making the game unplayable. The PC in question was an AMD Athlon 64 with nVidia 8800GT using Windows XP 32-bit. The only solution seemed to be to run the game in windowed mode.
The other PC, an Intel Core 2 Duo with nVidia GTX260, had perfect graphics in both in Vista and XP.
Both PCs use IE7 so I don't think it's a browser issue. Both PCs are dual-core, both have 4GB RAM, both have identical sound cards. The only real difference (other than processior brand and motherboard) between the two PCs is the graphics adapter installed in each, with the game failing on the 8800GT card.
Both PCs (in all Windows versions) had the looping sound problem reported elsewhere.
Edited on 01/19/2009 at 6:27:58 PM PST