When I purchased my Gateway about 18 months ago, it had 1 hard drive, 512 meg of RAM, and used the onboard video. I have since added a 2nd hard drive, another 512 meg of RAM, and an Nvidia geforce 5200 video card. I've noticed recently that the CPU fan turns itself on and off quite a bit. Is it possible that the additional hardware has raised the temperature inside the case? I've never upgraded a fan before. Are they rated by the RPM, the BTU's of cooling power, something else? I assume there are dealers that I could call with the current fan specs that would be able to tell me if they had a compatible fan, right? Thanks for the help.

Have you ever cleaned out the dust buildup in the heatsink? Do that and see if your temps drop any. Unless the fan is becoming noisy or your temperatures are climbing there is probably no need to replace it. If you need a utility to check your temperatures, other than the BIOS System Health info then get a prog called Everest Home Edition. Among a multitude of other info about your system it also will access your onboard sensor chip and show you the current operating temperatures. I used to have a signature but it disappeared and I just couldn't be bothered writing another so please feel free to ingore this.

Are you sure the noise you hear is the cpu fan? Did you open up the case and monitor the cpu fan for a while? Some mboards have the built in ability to run the cpu fan faster/slower depending on the temperature inside the case or of the cpu, but it never stops spinning while the computer is actively operating. Some case fans have temperature regulated controls and may fun faster when the temp inside the case is higher, and run slower or stop spinning when the temp is lower. Some more advanced power supplys have fan that will spin faster when the computer is loading the PS more, but they are usually relatively quiet. Your Gateway isn't likely to have a more advanced PS, or temp controlled case fan(s) unless the ability is built into the mboard. Another culprit is some CD/DVD drives are noisy when they spin, especially when they spin faster. Most people don't realize that if you have a CD or DVD in a drive, Windows will spin the drive while booting, and at seemingly random times while you are using the computer, whether you are trying to access the CD or DVD or not, often without turning on it's led. Remove the CDs or DVDs when you aren't using them and see if the noise goes way.