Unsuccessfully tried to add memory, now PC won't boot up!

[BT5150]

I have an old HP Pavillion 7955 that I got from my Dad that I was trying to add some memory to. I encountered a couple of problems in the install and now the whole machine will not boot up. When I was inside the case, I was using an air blower can to blow out the dust. There was a lot of dust in and around the fan directly on top of the heat sink for the processor, so I tried to unlock the clips holding the fan on to the heat sink when one of the clips broke. Now the fan sits rather loosely on top of the heat sink, it is still held in place by one of the clips. When I tried to install the memory, I realized it wasn't the correct type for that PC, so I aborted the install. I put everything back together and now the PC won't boot up. When I press the on/off button on the front of the PC, it will sound like it is beginning to start up and the led below the on/off button will light up for maybe 10 seconds and then will go off and nothing happens, nothing appears on the monitor at all.

Does anyone have ANY ideas to try in this situation? I could really use to get this thing going again, thanks!

[Phaelax]

You might have knocked the cpu loose. I'd open it back up and check every connection. Also, if that heat sink isn't sitting properly on the cpu, it could overheat very quickly.

[BlackFetus]

..try to check the cpu and heatsink settings..also, check the wired panels in your motherboard..^_^..

[PcTestCard.com]

Try reseat the CPU and fix the loose heatsink.

PC will power off if CPU is overheated.

Hope this helps!
Bill
Tech manager

[Problem Solwer]

You only check the memory chip which is instaled correctly or not.
Olso chek the wires of hardDisk are conected or not then conect them.