upgrade project - not quite working, help please

[Elyone]

hey all.

I am trying to upgrade an old computer and you know how it is - like the story of 'I have my grandfathers ax - my father replaced the handle and I put on a new blade'.

I did a comedy of errors, please do not poke fun, I already berated myself enough...

OK here we go:
My old comp died (the HD was not longer being recognized and it was not the HD - i tried it on another comp). I thought it was the mobo, so I bought a cheap (NOS) mobo off ebay.

Foxconn 915pl7AR-8S (circa 2004/5?) It's a 775, FSB 800, 915 chipset, supports DDR1. (Old, I TOLD you so) total cost: $20.
I then realized my old chip (a 478) will not fit of course. So I bought a new celeron, from newegg. It says it fits LGA 775. Good, no? (cost: $50)

I also threw in 2 gig of RAM (Crucial 2x1 kit, $21.49)
Of course the RAM was 240 pin, and the mobo supports 184 pin. /sigh So there goes $21 (I'll sell it for $20, shipping on me if anyone is interested. It's unopened)

anyway, I put it all together; I used my old PSU, disks, ati card (FGE slot), RAM, CD drive, and case.
It turned on, everything whirred but nothing on the monitor.

OK, I thought, Ill get a PCIe card, it must be the card.
I got another NOS off ebay, an ATI X600pro 128MB AIW. ($24)

Still nothing. The fan on the vid card also spins, everything is on, but nothing on the monitor.

I tried to remove the RAM and disconnected the HDs, still nothing.

So so far I stupidly wasted ~$110. (Sheesh, I did not realize that. /slaps self')

I am now afraid the chip is wrong, even though it fits the board. It said on the mobo 'supports Pentium 4, LGA775, Prescott processor'. I tried to find a Prescott but they are obsolete. I figured that any 775 chip that fits, should work.

Anyway, should I just learn my lesson, throw it all out and look ahead? Get a more compatible mobo? Anything else?

Thanks

[Apoptosis]

Do you have a big enough budget to start back over and get an LGA 775 system or are you out of cash?

[Elyone]

Hmm, i well I could put in a bit more. I guess I would need a newer mobo, right? Well considering I already bought the chip, and the bought RAM, have CD drive (non SATA), PSU and case, what cheap, simple mono should I get?
My main comp is a core i7 I built in Jan (I love it) this will be for my kids, and I figured it would be easy - guess I was wrong lol.

[Major_A]

Sounds like...
1. The power supply you are using is bad. And that was the initial problem (minus the unrecognized HDD).
2. Something is grounding itself inside the case. Remove the "guts" from the case and try to boot the PC that way.
3. You don't have all of the power supply connections hooked up. Is the 4 or 8 pin power connection for the CPU hooked up?

*EDIT*
After looking at Foxconn's website (your model isn't there but I found something close 915PL7AE-8S) maybe the newer Celereon just isn't supported. I couldn't find a list of supported CPUs for that board either.