Hello...im new to this forum. and yes i know there are soo many threads with not booting up computer, but i cant find the info i need.

alright heres what happened. I bought a new cpu cooling fan to replaces the stock one. i removed the side panel, then forgot theres a cable to the cleaning fan which popped out. But i thought no biggy cuz it just came out of its connector. Then i removed the stocked cooling fan with caution. Cleaned the cpu with rubbing alcohol. Then pasted some thermal paste that came with the fan. Installed everthing correctly NOT TOUCHING ANYTHING ELSE. finished right...I turned on my computer, no noise at all and then my moniter does display anything!!!. all it says is no signal. I heard the cd rom run for a lil but no beep that i usually hear. Waiting a lil i hold the power button down to shut it off and it wont. the only way is from the back. So i decided to take the fan out and put in the stock one again. After doing that i turned on the computer and still nothing. I checked all the cables and the same to be correct. I uninstalled and reinstalled the video card...still nothing.

So my question is what happend? i didnt touch anything but the cpu cooling fan. PLEASE someone if you know help me plz.

thanks

I feel for you. Sounds like something fried.

It sounds like you may have either something disconnected or a short in the power system which is preventing the system from turning on.
Check the basics:
1. Is the power cord connect to the mains?
2. Are any cables disconnected inside the case? (power switch)
3. Power supply connector to motherboard
4. Is processor properly seated?
5. Was processor die damaged during removal or installation of the heatsink
6. Is the heatsink fan connector installed on the correct motherboard connection and not reversed
7. Is the "cleaning" (I assume you are refering to an exhaust fan on the side panel) fan connected properly?

I have win me with the same trouble. All I did was install a new cpu fan. I have checked all of the suggested points to no avail. I think it's the mobo but I dont want to change parts blindly.

was the computer unplugged during repair?????

that would explain it if it wasn't.

It certainly concerns me to hear of a heatsink/fan unit being replaced in this way.

Definitely, power cords should be disconnected.
Preferably the motherboard should be removed from the case and supported on a flat, cushioned surface. The pressure involved in clipping and unclipping a heatsink is enough to crack the motherboard of it is only supported by the spacers.

It could be quite fine. Check that no other cables or connectors were bumped llose during the job. Reset CMOS and try to reboot.

If no joy, then a technician is the best way to proceed.

Catweasle i have to thank you...

i have had this argument with my brother over the last two or three days. he's been trying to replace a stock AMD heatsink and cooling fan assembly.

just for the record most of the time you will have to remove the power supply unit from the case in order to get to the mobo to take that out. when its out its best to put it upon a antistatic surface and ensure that you are still grounded ok. we dont want to frazzle the board and it only takes something like 1 millivolt or something to fry that board (quote me if i'm wrong please). your mobo is really just a massive PCB with more than enough data lines then i'd care to imagine so to speak.:cheesy:

The power supply switch was in the off position, I had hoped that would suffice. The possibility of a cracked mobo is high although I couldn't see anything on the component side. thanks for the help. still looking.

If the power supply unit had an isolation switch and that was turned off you are pretty safe from electrical damage. The isolation switch disconnects power from the motherboard.

Power down again, turn that switch off and check that ALL cards, RAM modules, cable connectors etc etc are firmly and securely pushed home in their slots and sockets. Something may have worked loose.

I've taken the whole pc apart, wires, cards, and processor. I removed the mobo from the case and gave it the best visual inspection I could without a magnifying glass. I put it all back together, checking wire positions carefully, and guess what! same problem. I think it's the mobo as orrigionally suggested. Possibly a cracked solder connection I just can't see or maybe just fried. I'm going to see if the local techs have some way of testing the motherboard.