This is more of a comment rather than a question but replies are welcome. I installed Windows 7 RC on a Compaq d530 CMT computer about 8 days ago. Yesterday is when I first tried using flash drive with it. Win 7 displayed a message saying a valid driver was not available and displayed a yellow triangle in Device Manager in the Universal Serial Bus Controllers section. I deleted the device in Device Manager, restarted, tried the flash drive again, and got the same response.
Today, I tried a flash drive again and Win 7 accepted it as normal. I have no idea why Win 7 changed it mind.