Just built this comp, and after installing the XP Pro update, mobo, mouse, and graphics drivers and restarting from time to time, the optical mouse decides its not gonna work anymore. Its a PS/2 / USB optical Logitech MX310, all drivers installed, and when I hook it up through PS/2, the light turns on under it, but the cursor won't move, and when I use USB, it detects it as a USB device, but the light wont turn on. What's weird, too, is that after the comp's turned off, the mouse stays on. It's probably a problem with my mobo, though, as my old mouse won't work either. It's a Chaintech 9PJL3 INTEL 865PE+ICHS R, and USB 2.0 hasn't been configured yet. Any help greatly appreciated! Thanks much.