Here's one that's been roasting our chestnuts for two weeks now. Newer XP machine, virus & malware free*. We can ping, update apps, IM etc all day long. But to surf with either IE or FF we loose conectivity after ~a 15 minute instance. Reboot brings back browser function for another ~15 min's. If we exit the browser before we loose connectivity, we can open it back up and continue surfing... aggragate time does not cause loss of connectivity.
Thoughts or ideas? No, linux/mac isn't an option.