Q6600 is getting long in the tooth, but far from obsolete. Rather than getting a 2TB hard drive, look at getting an 80-120 GB SSD for your OS (fresh install) and programs. Keep the 320 GB drive for data storage only. Add in a newer graphics card (GTX660Ti comes to mind) and you should be good to go. A good dusting and your system should be good for another couple of years.