Hello:

My O.S. is Dell dimension 3000, win xp, home ed., sp3

I recently re-installed windows and some applications so now my computer works very well and FAST - BUT.........
the cooling fan is always on and RUNS very hard. I am wondering if anyone can explain what the fan is trying to do and why it runs so hard these days.  The CPUID hardware monitor app. shows: 96° F right now and the fan is blowing pretty hard.  There was a time when the fan was much quieter. The computer seems to be working just about as good as it did when I re-installed things and many virus scans have turned up no malicious problems. When I re-installed windows, I cleaned out the inside of the tower so I don't believe the fan is trying to make up for accumulated dirt in the tower.  Also, I downloaded a Bios updated driver from Dell and installed it but no change in the fan speed.  I'd like to understand what is going on with the fan and, if it's a problem, fix it soon.

Thank you for your help here,
Jim    Good evening jimrich and WELCOME to CH

When you cleaned out the inside of the PC did the shroud around the CPU / Case fan get closed back down the one I am TALKING about should look like this

Plus when you cleaned the PC are both green clips in place on both sides of the heatsink if the heat sink is not right on top the CPU it will call for the fans to run at top speed

Mike  +1 Hartbeatmr's post, also:

Did you install all appropriate drivers starting with the Chipset drivers?
Some motherboards require a driver to CONTROL the fan speeds inside Windows and/or to control the processor speed to help reduce heat output.