I have a Celeron 1.8 / Asrock Motherboard / 128MB RAM PC running Win-XP.Recently it had a problem with RAM and I replaced it. However I had opened several of the connections inside. Later I reconnected them following the connections of another working PC of the same configuration. After that the PC doesn't boot at all. On switching on, the green light glows, SMPS fan and processor fan rotates, CD tray may be ejected but booting beep is not audible. What to do?