If you aren't getting any beeps on the RAM, chances are the mobo is dead. Try pulling the graphics card as well, should get a couple beeps on that.
Turning on and off the computer wouldn't do it. He could have been using a substandard power supply which can kill components quite easily.
If this was a new installation, I'd think the motherboard could be shorting itself out somewhere, but this isn't the case.
P4 2.6C, Thermalright SP94/Panaflo 92MM M1A, IC7 Max3, Swifty MCX159, 1GB Geil PC4000 Ultra Plat, Radeon 8500, Audigy 2, 2X WD Raptor RAID 0, WD 250GB SE, Plex 708A, 166SDVD, LianLi PC75, XP Pro.