While installing XP SP3 my Dell XPS 400 desktop crashed, cannot make it work no matter what, safe mode is there but same BSoD appears even while trying last good known config, diagnostics shows everything ok, but as I was trying to re-install XP got msg with no hard drive found! checked cables and PSU, everything checks out, tried changing video card and got same error ... what should I do? BSoD reads: Stop: 0x0000007E.