Found the problem! It's the Mircosoft Virus...
Honestly, the computer that I use came with a 2.4g processor and 512 RAM. Supposedly upgradeable to 4g of RAM, so I tried, crashed left and right. Ended up with 1.87g of ram and it works perfect, hasn't crashed since, running Windows XP.
Are those problems related? Not sure. Could have been that my processor and or motherboard just didn't like all that RAM, but it did only really give me problems running Rhino, which is the main use for that computer.
I had another computer which is now dedicated to a machine running Mach3. I paid a friend to build it, 3.6g processor and 1g RAM. I've made some VERY complicated parts, and when Rhino would bog down my normal computer, I used to transfer everything over to the 3.6g processor computer because it would run so much smoother. For instance, splitting very complicated surfaces, or generating very complicated tool paths in RhinoCam would take up to 60 seconds on a 2.4g processor, about 10 seconds on the 3.6g, and I wouldn't have to worry about the program crashing either.
Maybe too much RAM and not enough processor? I'm only guessing, but my experiences seem to follow along with yours.