CPU fan causing shutdown

before the computer has even booted up.

I did a search and could come up with nothing that sounds like my problem so please forgive me if this problem has been addressed before.

I have an HP pavilion a815n desk top computer, the cpu fan has been runnin non stop so I did as I have done to many times before, opened it up and cleaned all the dust bunnies out of it i did take the CPU fan off this time(i have before but not everytime) there was just so much dust in there it was caked on, put it all back together and plugged the fan back in (yes in the right spot), after hooking it back up and turnin the power on the fan started as it usually does on boot then the screen came up and then the fan like kicked into hi gear and shut the pc down i have tried numerous times and everytime is the same. any sugestions would be greatly appreciated! Thanks!

the sound you are hearing is not necessarily the fan, computers are doing a lot when they boot up. the other thing that can be a loud whirring noise is the cd rom drive, or it could be the hard drive.

If this problem is somethign that is happening after owning the computer for the year or 2, theres a good chance your hearing the hard drive going bad (or it is already bad), and it needs to be replaced. Most people characterize the sound of a hard drive with a crunching noise though.

Other things to do...

-try booting into safe mode
-try booting into the bios screen ......just to see if you can get that far.

if you can get into the saafemode/bios screen, try disabling some extra features, unplugging some extra devices. You might be experiencing power or overheating issues.

also, just for fun, try a different power source (plug it into a different wall).

edit: something else to try, look for heat sensor wires, maybe it got moved to a place in the CPU that it shouldnt be, and its shutting off the CPU thinking that the computer has gotten to hot.

if you press the F8 when the computer starts and if takes you to bio then you can check if it is the fan, go to hardware monitor and check what is the temperature. if it is above 60% then it is.

Sometimes when you clean the fan and if you take out the aluminum chassis from the CPU it loses the adherence when you put it back and then because it doesn't have good contact with the chip the temperature can sky rocket....

another thing is, a lot of desktop computers now come with those little tunneling things to help air circulation (usually made out of plastic or something). hopefully if you had those, you didnt take them out becasue their important for the cooling of the system.

I think when you clean the CPU fan .You may be done something wrong with you fan .But I am sorry I have not yet ran into a similar issue...

Use vacuum cleaner when you clean CPU fan.