Old PC: speaker clicks, no other signs of life

I'm trying to revive a very old build that I think just had a bad power supply when I put it aside years ago.

The problem then (late 2009) was that the motherboard and case power LEDs would illuminate when I pressed the power button, but nothing else happened.

For a long time, I assumed the motherboard had simply died. Recently, I acquired a new power supply and, while waiting on the rest of the parts, decided to give it a go in the old system.

The system now shows partial signs of life. The case and CPU fans spin, but there is still no video signal. The only response is a pattern of 2 rapid clicks, about every 2 seconds, through the PC speaker (yes, that old-skool little speaker attached directly to the motherboard).

Things I already checked:
-The video card (Radeon x1650 Pro AGP 8x) is connected to the proper 4-pin power plug.
-Reseated the RAM, and double-checked the configuration with the motherboard manual. Also tried powering up with no RAM installed - which gave the correct beep code (one long tone, repeated every few seconds).
-Cleared CMOS.
-Replaced the BIOS settings backup battery (a 3 V CR 2032 coin cell). Old one was at 2.85 V, new one reads 3.05 V.

Two other observations:
-the numlock, capslock, and scroll lock LEDs on the keyboard illuminate briefly on powerup, but are then unresponsive, whether the keyboard is plugged into a motherboard USB port or PS/2 port (using adapter).
-there is a fan on the motherboard, presumably there to cool part of the chipset, which does not turn. This may be why the system stopped working in the first place (maybe the northbridge or southbridge is fried?), but I can't say whether it was normally spinning at startup when the system worked.

Any ideas? It would be great if I could get this old system working again. I was about to throw it all out.

Here are the specs:
-Abit NF7-S v2.0 motherboard
-AMD Athlon XP 3200+ CPU
-1 GB (2x 512 MB) DDR 400 MHz RAM (PC 3200)
-ATI Radeon x1650 AGP 8x video card
-One 60 GB IDE HDD
-One SATA DVD-RW drive

Have you tried reseating the graphics card?
does the motherboard have onboard graphics? if so have you tried removing the graphics card and using it?

No onboard graphics (it's the NF7-S model; only the -M model had onboard graphics).

But I think I figured out why the board doesn't work. When I power it up, the CPU cooling fan and any other fans plugged into the motherboard will spin.

Except for the northbridge cooling fan. It is in a metal enclosure that was seated directly on top of the large northbridge chip with thermal paste. It's supposed to run at all times, and when I hooked up a known-good fan to its socket, indeed it ran continuously.

Presumably, here's what happened: At some point, the northbridge cooling fan died. Shortly after, the nForce 2 SPP northbridge chip fried itself.

I'm pretty sure I could solder in a new nForce 2 SPP, but at this point it's not worth the trouble of tracking one down and doing a replacement. For all I know, some other component is bad as well.

do you get any beeps from the buzzer without any ram and no vidcard? if no, then yup, dat nf2 be gone. you could try cleaning off the old thermal interface material from the chipset and applying a new layer... might give it just enough cooling to power on if it isn't totally fried.

Have you tested the mobo outside the case, to rule out a short on top or bottom, probably around a mounting hole but maybe also at a corner?

I'd look at the DIMM sockets under bright light, in case a contact is mangled and shorting something. I'd also try just one DIMM at a time because some 400 MHz bus speed mobos can't handle that speed with more than one DIMM installed. Is it possible the memory is good enough to pass the BIOS's power-up test but not boot?

I don't know if the north bridge can burn up from its fan not running, but I've seen nForce2 and nForce3 chipsets whose fanless heatsinks didn't have much more metal than fanned heatsinks did.

I'd try a PCI video card or at least a low power AGP card that doesn't need a separate power connector.

I don't think this mobo has capacitor problems because it was made with high quality Rubycons (large "K" stamped in their tops), which rarely fail in Socket A mobos.

Here's the semi-amusing denouement.

The motherboard I bought for a new system is broken for a second time. It broke, I RMA'd it, they fixed it and sent it back, then it broke again.

I got so fed up with this that I bought second, brand new motherboard of a different brand. I'll be sending in the now-broken-again board for warranty service and, presumably, get it back in working condition eventually.

So I already have a spare power supply to build yet another system, will have the motherboard soon, and don't need a video card since the Ivy Bridge CPUs have video built in. Even have some spare DDR3 RAM, and a spare HDD. I've still got the old case mentioned in this thread.

Only thing I'm missing is an additional Ivy Bridge CPU.

I don't know what the heck I would do with it, but it will be tempting to put something cheap (say a Core i3) in there and have yet another machine. Maybe make it into a Hackintosh or dedicated Linux box.