My friend built a PC recently, and it was working (somewhat) until today...

the fan on the mother board doesnt spin
the computer doesnt boot. Upon pressing the power button, no drive activity can be detected.

I have checked power connections, everything seems in order. We thought the power switch might be the problem, but crossing the wires didn't solve the problem...

All the equipment inside is new, except for the primary master drive and the DVD-ROM drive...

If anyone has any idea what could have caused this, I could use a little help. I don't see any obvious burn marks or anything either...

Could have bad memory, that is what was wrong with mine...

Mine wouldn't boot or anything, but once the mem was replaced, everything worked perfectly...

friend says the memory is brand spanking new, proper voltage and pin number...

So was mine, but it died on the second boot up. Put in a spare that the guy had, and it worked fine for several boot ups.

Lesson us Mechanics know by heart: Just because it is new, doesn't mean that it isn't junk.

I see... well, i'll check on it...

I agree, Alex, try taking out the RAM and substituting in any old RAM and see if it works.

check the processor and Mobo also if that don't work

Are you sure you have the power supply connected to the mobo right? If it uses two connectors side-by-side, make sure the black wires are on the inside of the two.

i doubt its bad mem, the mobo would still boot before hitting the bad mem and stopping. Even if you take out the ram completely, the mobo still turns on, and attempts to boot (obviously stopping when it hits the no ram thing, but it still stays on)

1) test the PSU (force it on by jumping it)

2)read the mobo manual and make sure there wasn't anything special you had to do

3) make sure nothing metal is touching the mobo (front or back)

Bad MEM stick caused mine to not boot at all, it would turn on, but not boot or do anything.

with the fan not spinning, I would have to say mobo or psu

Yes, this I know. If you read his problem (very, very carefully) you will realize that its not turning on at all. (Hence the "fan not spinning" thing - this means he isn't getting any power at all, so either the motherboard has stopped the PSU from turning on, or the PSU don't work)

If you have a multimeter:

1. http://hardware.mcse.ms/archive10-2004-9-82101.html
2. Then try measuring across black/red and black/yellow (use the black closest to the respective color). See what voltages you get.

Oh, and make SURE you have an FDD or CD drive connected before your force it to give it a load.

I usually leave the fans connected - its easier to tell if it goes on

But jumping it would be bad for the fan, so keep it unplugged. am I correct?

totally not

fan(s) stay connected to PSU. Jump the PSU to "trick" it into turning on (similar to how the mobo turns it on). If fan(s) spin up, your PSU could be fine - just test the voltages to make sure its within spec

not at all. Wouldn't injure it a bit.

Yeah, i'll see what i can do...

On the plus side, i'm going to start building my new PC soon... does anyone here have any parts they dont need, and would sell cheap? (meh... i dont wanna drop $1200 into a processor... no matter how good the FSB is...)

I've got random various and sundry, but shipping would be more than shipping+cost on ebay.

$1200 on a proc??? dude, I could build a (brand new) kickass PC for that much....

Oh, and the FSB only matters on Intel procs (All new AMD chips have the same FSB, and it has a much lower impact due to the integrated memory controller)