Is it a bad idea to try adding a case fan...? I've done a fair bit of metalworking before and I was thinking of cutting a hole in my case and mounting a fan in it to keep it from getting too hot. I don't turn my computer off very often so I don't want it to heat up too much.. I also wouldn't mind trying overclocking it to be able to play some games better.. i've read about it before and saw a friend doing it...

If you wan to overclock you're computer I would definately recommend adding a case fan. Overclocking causes more heat, and you don't want to be overheating or melting anything! It's not too hard to do, it's just metal... Steer clear of any parts of the case that are close to anything inside.

If you are overclocking your system then adding a case fan will NOT do much good for cooling of the CPU and RAM etc.

Adding the case fan is a good idea though, just don't expect it to solve all your needs.

Think about buying a good CPU cooling system (a large heat sink and fast, reliable fan). Also RAM coolers, HDD fans etc all help in cooling your system down alot more than a simple case fan will do.

Also remeber that case fans need to be positioned properly so that they work well with the other case fans you may have. Generally 1x120mm fan near the front to suck cool air into your case and either 2x80mm or 1x120mm fan on the back of the case to throw all the hot air out.

If all your fans face into the computer and blow air inside, then hot air will escape slowly and the temp will slowly rise.

Generally the more fans you have the better, as long as they are placed correctly and are up to the job, you should be ok. Just banging a fan on the side of your machine will probably not help your cooling and if you overclock the machine, you will certainly need to upgrade your heat sink and fan, especially as you mention that you rarely turn the machine off.