Monitor your temps for about 4-5 days and keep an eye on the highs and lows.
You can also check the following situations:
1) Does the space you keep the computer in have adequate ventillation? Stuffing you box under your desk or in a corner may keep it out of the way, but it does it no good when the only air it pushes around is the same air it heated up just a few minutes ago. If it must fit in the corner or under your desk, get a fan to circulate air into that closed space and keep it at least 4 inches from any solid surface like the wall or your desk.
2) Blow out those dust bunnies at least once every 3-4 months. This will mean actually unhooking your computer, taking it out to the back porch or garage, and going to town with a can of compressed air or your vacuum cleaner attachment.
3) Take a look at you case. Does it have proper airflow? Do you possibly need more case fans? Look for big, slow 120mm case fans that move a consistent amount of air without making a lot of noise. Did you manage the cabling inside your case to allow for better airflow? Sometimes this makes all the difference in the world by eliminating airflow dead spots.