ASUS A7V with 1.2GHz AMD was working perfectly fine. For no apparent reason (no new applications loaded, no updates run) it won't power down now. Start-Shutdown-Shutdown from Win98 goes normally until the point where power should turn off. Everything stops there showing either a black screen with a blinking cursor, or a white screen with static color noise. The power button doesn't work and if I push reset it goes back into Windows like it was booting up. The only way to kill power is to pull the power cord. Any ideas?