CPU temp = 89 degrees celsius!
 

Clearly this temperature is WAY hotter than it should be. Heat is radiating out the sides of my laptop; I even have it propped up so there's air underneath. That helps a little bit. It really only spikes like this whenever I'm doing some sort of CPU-intensive encoding task.... otherwise it hovers around 45-50 degrees. Does anybody know how detrimental it is to the processor to be overheating like this? By how much does it decrease its lifespan?

What kind of CPU ist that?

There isn't a solid ratio for how much is kills your computer's lifespan, but it's safe to say that things are likelier to crap out if they're burning hot. The biggest risk is that it can damage the motherboard, which is never a cheap fix in a laptop.

I'd open it up the best you can and blast it clean with canned air. Adding fresh thermal paste wouldn't hurt, but that's not a simple task for most people.

Intel Core 2
T7200 2.00GHz

I've actually never opened a laptop before; I've only owned one less than a year. Any sort of precautions I should take compared to opening up a desktop (which I've done dozens of times)?

A common misconception is that any contact inside a laptop will cause it to burst into flame, so don't worry too much, just use the same caution you would with a desktop and you'll be fine. If you remove all the screws on the bottom of the laptop, you can usually open the case up enough for the purpose of cleaning it out. Don't worry about getting it to separate, you just need access inside to blow the dirt out. Most of your effort should be cleaning the heatsink and fans, since that's where your trouble likely is.

Will do. Thanks a lot for your advice.

Yeah, I'd recommend his suggestion, as my old laptop once started to heat up pretty bad that I actually tried to cool it down with a bag of ice. :lol:

But after I blew/cleaned the fan and heatsink, all was well.