[jyl]

Make sure all the fans and heatsinks are working, clean, and unobstructed. If this is a stock PC from a reputable company, not being overclocked, and you haven't added heat sources, it should be designed to cool okay.

Also make sure it really "is" running hot. Use an app that uses a temp sensor(s) on the motherboard (I used to use Motherboard Monitor, a bit of shareware) or actually get a temp probe.

If that doesn't work, then:
- check the exhaust path. A lot of computer cases have plenty of noisy fans pushing air in the front, but not much room for air to exhaust out the rear. You can install an exhaust fan, drill holes on the top or sides of the case, etc.
- fancy and effective aftermarket heatsinks are available. Thermal paste is a good idea too.
- sounds crude, but with cardboard and tape you can make nice little ducts to guide air from a fan(s) straight to the CPU.