If the above mentioned solutions don't resolve the issue, you need to check whether the Amount of RAM is sufficient or not. For instance, if you would like to run Windows 7 operating system, there should be minimum 1GB RAM. Now, if your computer has 512MB RAM and you have installed Windows7, it is quite obvious that you can never get the best out of your PC. Besides, most of the latest computer games require high resources. So, add more RAM and you will find a significant boost in your PC performance.