I bought a internal media card reader and when I hook it up the computer runs every slow because of 100% cpu usage if I unhook the card reader the computer runs fine. With it hooked up if I put my usb key in to it the computer will lock up. Is there a problem with the reader I got or with the usb header on the board?

First, I would make sure that your driver is good to go in the device manager found by going to control panel,system,hardware, and device manager. If it is showing a usb connection for the card reader in the usb drop down menu, then there should not be a problem with the usb itself. However, another thing I would try, is I would unplug the card reader, then get rid of any extra usb connections other than those that are motherboard based. Reboot, go back and make sure that they did not reinstall themselves. Turn off your pc, plug in the card reader and reboot and see if XP installs and try your reader again. Lastly, if power is the issue after all, you can buy usb hubs that have their own power source and do not tax the system. I would buy one from NEW EGG. Hope this helps.