Getting BSOD w/error that says caused by usbport.sys; does anyone have any idea what could case this. The computer may run for days, hours, or weeks and then start shutting down. After a shut down if I leave it off for 30 secs and then retstart it may run again for an indeterminate time period. I have changed hd, formated and reloaded 3 times but cannot fix the problem...help..please.