I have an IBM Thinkpad, and I can run Source games fine on it. However, more recently I've been getting Direct3D errors. All of a sudden the game will shut down with an error that includes Direct3D in it, or the game will fail to run at all.

Specs so you fags don't go "GET BETTAR COMPUTER LULZ", I have a good desktop machine it's just fun to play on a laptop.

2 GHz Pentium
1 GB RAM
ATI Radeon X300

I just got the most recent drivers too, so yeah.

HELP PLZ

Check your fan, sometimes they collect a bunch of lint and dust and heat up. It may even, as you probably know, start a fire. A fast fan isn't always a good one, It can heat up your computer more than it was before. I suggest you clean out your fan and see if you can't find something like one of those fan pads you set your computer on(it blows the heat away. And generates less heat)(recommended). Or look for a fan of good quality to buy.

a fan pad will cool the bottom off while the fan inside will cool off the area its in.

what does this have to do with derectX? allot.
If you computer a laptop heats up too much, it can damage your chips and stuff. I don't know if this is your problem or not.
hope I helped

try overclocking as well:

http://en.wikipedia.org/wiki/Overclocking

although this could possibly make the fan worse (if thats what it is). try rawgreens idea, and if that doesnt work, try overclocking, but i have a feeling it isnt a problem with your computer's performance