Go into BIOS settings, if you have it put the XP CD in the CD or DVD drive, set the BIOS to boot from the CD device, power off the computer, power the PC back on, do a repair if given the option.
Otherwise boot the PC and go to the built in Repair/reload partition on the hard drive. You may be able to press F10 when you see the first text or graphic on the screen when you see the PC manufactures name or a BIOS message displayed. There may be some other key stroke command needed, check the owner's manual or with tech support.
Let's hope isn't the following issue:
If you did not pull the MODEM/Phone cable or DSL/Cable MODEM cable you could pick up a surge from 50 miles away, even greater distances are possible, from your house. A buried or open phone line running to an un-attached garage could pick up the spike locally. The house's electrical ground could be faulty and let such a spike into the house as well. A lightning ground strike can induce 300 volts, and possibly more, into a cable or telephone system. It is like an EMP strikes from Mother Nature. The spike will only last for split second. The lights won't flicker and fridge won't miss a beat, but the PC will get gutted. The protection devices on their (cable or phone) systems can still let spikes into your home.
I have seen PCs in the depot or customer returns section with the motherboard cooked where the built in MODEM or network card was located or the slot fried where a card was inserted. Others main boards showed no external signs of damage but started having odd problems that builds up to crash the system. I would check the regional storm reports and inspect all returns with suspected storm damage for the records. My old Electronics instructor, was a retired Goodyear Electrical engineer, spoke of such things from experience.
Good luck! One can only hope it may be something simple and unrelated to the storm.
(Formerly a COMPAQ service dispatcher & field service/customer helpdesk engineer for a North American account.)
