Hi, I have a windows XP desktop which has a USB1 card integral to the motherboard. We got a USB2 300Gb removable hard drive and wanted to use it with a USB2 port, so we got a new card. The PC has 4 slots, the second one is for the video card, which physically blocks out the top slot. We added the new card to the bottom slot, but it wouldn't work there, no idea why. So we removed the network card (which we don't use) from the third slot and put it in there & it worked. So far so good. When I add my USB stick, which has always worked before, it would not show in My Computer, or if it did, you couldn't read or write to it, no matter whether it was plugged into the old or new USB cards. When I connect our Olympus C750 digital camera, the same problem. Both USB stick & camera still work on other computers using the same Windows drivers as before. Sometimes the computer 'sees' my USB stick as the 300Gb removable drive, sometimes as what it is, sometimes not at all, but it nevers lets me read or write to it. I tried formatting the USB stick but it didn't help. Any ideas?