HELP WITH BEEPS!!!

Ok, here it goes. I recently got a computer from a friend. It is really old, only 400 MHZ, you know the deal. I have connected everything correctly, and everything is ok in the system as far as I know. Both of the Hard Disks are blank, and the boot screens and everything worked fine, it loaded the BIOS stuff, and I would have installed my OS, but i didn't have the sopy before my problem arose. I was about to install windows 2000 to the system, all I got were an endless amount of long beeps as soon as I pressed the power button, and no signal to the monitor. The video card is built in and the RAM is connected correctly, the hard disk light is always on, however. Hopefully my problem is something stupid like a disconnected something or other, but i'm expecting the worst. I've seen related topics, and I've tried to troubleshoot from them, but my problem is different, so if anyone has a suggestion, it would be greatly appreciated.

Thanks,
The Novice

I would reseat / inspect every connector on the mobo including the memory (if it's a slot CPU do that too, very convenient).

Try to test the power supply standalone and the bare-bones config. If that is working then start adding one component at a time.

With systems that old you may want to replace the CMOS battery (CR2032 usually, if it is almost the size of a quarter) and only $2.50 or so. Then again it's a 400Mhz so that might be too much to spend on it

I tried both of those things, and it's not a PSU problem, and none of the components are problematic, i still need to get a new battery, and i will tomorrow. Any other suggestions in case that doesn't work?