Freezing synths and tracks with effects would lighten the load too. Running 64bit is going to make the problem worse unless you add more RAM.

Hi Eric,
 
If you're making fairly moderate use of soft-synths (especially those that load samples into RAM), you can quickly/easily blow thru 3GB.  That could be what's causing your stability problems.
 
FWIW, I don't recommend installing the latest generation OS on older hardware.
That's almost begging for problems (high DPC Latency, etc)...
If you have a copy of Win7x64, I'd re-install with that... and get the RAM up to at least 8GB.
That would be a much more suitable configuration (given your hardware) for running soft-synths.
 

Thanks everyone for the input! It has been really helpful for me as I have always dabbled in recording because I'm a songwriter and dont want to spend an ass load of money to lay down demos in a pro studio. To be honest, all I saw on the specs was the Intel Core 2 Duo and I assumed my dual core AMD Athlon would be sufficient. I guess AMD and Intel are different? Once again thanks alot and you've helped me realize I need more CPU and Ram. It's kind of like I knew it would come to that but I needed to hear it from someone else first before I broke down and bought it haha. Cheers!