customer brought in system cause sound card quit working when he installed new modem. Modem working OK. I re-seated sound card (always try the simple stuff first--right?) I turned the system back on and now it will only come up in "safe mode". Uninstalled sound card and modem both and removed the cards--system comes up with blue screen error message "virtual audio device" missing from system and locks up. Or will come up in "safe mode" only. Have tried everything in every combination but cannot get the system to come up in "normal" mode. Help!