Hi spencer boy. If the computer isn't booting at all, that is it doesn't give the usual POST (power on self test) beep, or show the usual black and white boot screens, then the problem is nothing to do with Windows, the hard drive hasn't been accessed at that stage. Diagnosis is mostly by substitution. First check that all connectors are seated properly, if that doesn't work try resetting the CMOS. Next I usually remove or disconnect everything from the motherboard except the processor with heatsink, a stick of memory, the power supply connectors (two of them for the P4), the graphics card, the power-on switch and the case speaker. If the computer still doesn't give the POST beep or boot graphics, then it is possible that the motherboard is shorting to the case, so I unscrew it and lay it on a sheet of card. Finally only substition can tell which of the few remaining components is faulty. The most common are the memory, the motherboard and the power supply.