Hello Jacob, and welcome to Vista Forums.
There's no need to ever have to manually clear your RAM in Vista. Vista will automatically clear anything not currently running from RAM automatically as needed.
You have 2GB of RAM, and some of that (ex: 512MB or 1 GB) is allocated for your NIVIDA GeForce Go 7300 graphics chip. That barely meets the bare minimum requirements for Vista alone. How much minimum RAM is required by the game?
I think the main problem is that your system just doesn't meet minimum requirements, and is being overloaded.
You could try cranking down the quality of the game's resolution and graphics for it to not use as much RAM if your computer meets the minimum requirements for the game.
In addition, check to make sure that you have a large enough page file
set to help with the overflow when your RAM is being fully used up.