Constant Crashing

So with the imminent release of GMod 13, I’ve been trying to get back into GMod, maybe try my hand at comic-making, but I have quite an annoying problem to solve before I can make much progress.
The game randomly freezes for no reason. Try to open the console? Crash. Open a folder in the Browse tab? Crash. Open the ‘Load Game’ menu? Crash. To add irritation to injury, the game makes a broken-record glitch of the last noise played.

Here’s some specifications just in case.
CPU: Intel Core i5 CPU (760 @ 2.80GHz)
RAM: 3.50 Gigabytes
Video: NVIDIA GeForce GT 430
OS: Windows XP Service Pack 3
I also one hundred and forty-six gigabytes of free space on my C: drive, so I’m at a loss. I also reinstalled and verified the integrity of the game cache, but to no avail.

Any help?

Are you trying to run Garry’s Mod or Garry’s Mod 13 Beta? Because GMOD 13 is very unfriendly towards XP users right now.

Regular GMod. I’m planning on getting Windows 7 eventually though.