Bitdefender 2011 just downloaded and installed an update and asked to reboot. I rebooted and got a BSOD. It reported that it was in usbstor.sys. I did a system restore and Windows booted OK. I did a Bitdefender update and rebooted again. BSOD again. I did another system restore to get Windows working again. So it's apparent that the update is causing the BSOD. What should I do?