Microsoft does not install proper motherboard drivers and sometimes the front usb ports are miswired.
Since you didn't offer details about the failing machines I can't offer the drivers I would install.
Read http://forums.cnet.com/5208-7588_102-0.html?forumID=70&threadID=220285&messageID=2331710 as well.
Bob
Bought a Cruzer 512mb, but find some pcs recognise it, some don't. Sandisk have a driver for it, but when I try to load it, it refuses, saying that XP does not require a driver. This darn thing is driving me nuts. Anyone got any ideas?

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