Old computer won't boot

I've just finished replacing the CMOS battery and the cpu cooling fan, now my system won't boot. I don't even get the POST beep. I've checked and double checked the connectors (both power and ribbons), reseated them, and reseated my ram but I still get the same results. Anybody have any suggestions?

Thanks,
mcgiddin

Why did you replace those things? Did it work before you replaced those things? What kind of CPU chip? When I hear old computer I think 486.

Its a Intel PIII Slot 1 500mhz system. Yes it did work before I replaced them. Well it worked two days prior, I didn't turn the system on to check it before replacing the parts so I guess its somewhat of an assumption that it was working. I figure that its either the MB or PS that's gone. I could have cracked the MB while I was replacing the fan, I doubt it, but anythings possible. I'm going to test the PS on Monday with a volt meter, and if that checks out I'm going to start swapping out parts with some old stuff that a friend has.

mcgiddin

Make sure your slot 1 is seated good. Pull it out and push it in again and make sure it "clicks." Maybe when you changed the fan, you dislodged it slightly. My first new build was a slot 1 (celeron 266) and I had the same thing. No beeps, nothing. I pushed down on the edges of the slot 1, heard a click, and it booted right up for me.