Please tell me I haven't blown my PC

[Dazzer]

I've had a problem with the CPU fan overheating.
So I opened up the PC, removed all the PCI boards and the AGP and all the cables and checked the CPU fan pins to see they were fully in. They were.
But on checking I noticed the fan was completely clogged with dust. So I carefully sucked this out with a vacuum.
But on reinserting all the cables and PCIs etc the PC won't boot. No BIOS appears on the screen.
The screen is connecting fine I think because I can see a change in the black.
I have checked and rechecked all the connections, but still I no joy.
The fans run fine, all three, and the SATA drives run. But there's no audio beep which you get on booting.
I've tried adding a Win2000 CDrom, but it won't boot from that either.
What have I done ... and how can I fix it?

Dazzer

Setup is:

Enlight EN-7254 ATX Midi Tower Case with 300Watt PSU
Asus P5P800 LGA-775 Motherboard
Intel Pentium4 530 LGA775 3.0GHz 800MHz (1MB Cache) Socket-775
Corsair 2x Memory 512Mb DDR 84 DIMM PC3200 NP CL3 for Intel LGA775
Sapphire Radeon 9250 128MB AGP8x DDR 64-bit DVI-I TV-Out Lite-Retail Box
Logitech Cordless Desktop MX
NEC ND3540 16x16 DVD±RW Dual Layer ReWriter Retail
2 x Seagate 250Gb Serial-ATA 7200rpm with 8Mb Buffer

[flanzig1]

double check that all the required cables are connected and fully seated. I had an ATX plug that looked plugged in but one side wasn't latch and the PC didn't boot. A 300w PSU maybe a little small and may have have given up. Also, make sure that the video card and ram are fully seated.

[Dazzer]

It isn't a new build. It's been working finr for around 8 months until I had the overheating problem. I've reseated the video card, but I'll recheck the ram and the ATX cable. Any further suggestions in the interim will be much appreciated. How can I check the PSU?

Dazzer

[bailey]

if the fan was clogged that bad, chances are pretty good that the heatsink fins are clogged too, double check that and you should blow it out with the canned air if possible, a vacume alone will not get it all out.

you should still get a post beep out of it. or somethings not connected good.

[Khalil]

I had a similar problem a few years ago and it was very frustrating. In the end it was the AGP card, it was not seated properly in the slot. It looked like it was but it wasn't. I would take it out carefuly, re-insert it again, make sure it is all the way in the slot, especialy the end that is near the side of the case. I also agree with Flanzig1 that PSU is way small for your rig.
Good luck.

[Dazzer]

Phew. It was the memory. Even though I thought I'd not touched it, I must have flipped off one of the holding clips. Only noticed it this morning, thanks Flanzig for suggesting the ram.
Vacuuming the dust out of the CPU fan has significantly improved the temperature control, but I'll get some canned air, thanks Bailey.
I'll look at getting a higher PSU too, thanks all. Much appreciated.

Dazzer

[Cricket]

You also need to include case cleaning as part of your computer maintenance program. You might want to open up the case and clean it out once a month or more if you live in a dusty location. Remember to take the face plate off the front of the case to clean the air intake vents too.

Cricket