ok here is my problem. i have an old computer 900MHZ athlon 384MB RAM PC133 GeForce MX4000 psu 400W And finally my problem. the computer ran good all the time but then it didnt start,i did everything cleared CMOS swapped ram ,bashed psu against the wall , EVERYTHING. then i gave up, put everything together and forgot about it, now this evening about 3weeks later i turned it on and it started ran everything OK, but then i turned it off with start, shutdown ,i turned it back on and i wont start again! All the fans are turning, lights are on, but no beep, and screen stays on standby.