Hi there,
this is my first post so if i miss anything out you need to know let me know.

I just recieved a new zalman 9700 cpu cooler. it required the mobo to be removed to fit it. so i removed al the wiring and fitted it (took an hour!). now i have tried to power up my pc after re assembling. nothing. no power light. no sign of any attempt to work


PLEASE ADVISE!!!!!!!!!

Try making sure all the wires you uninstalled are there, make sure the power pins and the reset pins are in the correct configuration. This config can be seen in the manual, this is most likely the problem. If not, test the PSU with a tester to make sure somehow it didnt die during the process. The pin problem is the most likely,

Yes, I agree with guitto. Be sure to check that all wires are connected to their original locations. Also, be sure that you didn't over tighten the screws when putting to mobo back in. Over tightening mobo screws could cause similar issues.

you may also have inadvertently fried the motherboard by removing it to hook up the fan. if nothing else we have suggested fixes the problem, it's pretty safe to assume that either the power supply is dead or the motherboard is. or perhaps even both. who knows?

you have to systematically test everything to see what's working and what isn't. i'm just warning you that a dead mobo could be a real possibility in this situation.

link590o has a very good point. Let us know what you find.

The best route from where you are now is just to go back to square one, carefully and with reference to your manuals, re-assemble from the beginning.
It's quite likely that you have forgotten something, or not seated a connection properly. There is also the more depressing possibility that you have caused some damage through a short, or static damage, but a while spent calmly putting it back together will hopefully work.

Also, don't worry about the opinion of anyone who considers himself an "expert", but cannot remember that he started somewhere too...

(That last sentence did make sense before the whole thread was edited)