Those technical questions regarding memory usage and limiting it would be best directed to online Technical Support Chat - see Useful Links above.
However, I don't think it's possibly, at least with the home product.
2008 products are no longer supported according to this page.
If your machine wont run the 2010 product at all and I assume you've tried perhaps it's best to move as the product auto-upgrades in time. The process can't be halted.