Comp keeps booting to BIOS

I’m trying to fix my friends pc. All it does is boot to BIOS as soon as i start it up, I’ve tried replacing the hard drive, moving the ram around, unplugging everything(cd-rom, floppy, all the PCI devices) the comp worked before hand until some kids got onto the comp and started pushing buttons . but i’ve loaded the default settings and it still will not boot… It saves the settings i give it, so i know its not the CMOS battery. It seems as if it doesn’t even try to boot anything up, then just goes straight to the bios screen. Oh yeah forgot to add, they havent added any new hardware, its still stock from ’03

Here’s all the necessary specs:

MB: ASUS A7V266E
Processor: AMD 2400+
RAM: 512 MB Corsair