We need a little more information than that. What's the specific error message that pops up?

Until then, here are a few basic things to check:

1. Make sure all your drivers are up to date.

2. Make sure your ram isn't faulty by downloading memtest86+

The blue screen of death, also known as the blue screen of doom or simply blue screen, is one of the most notorious error messages in Windows based operating systems. To fix blue screen errors, you can safely assume that there's something going seriously wrong in your operating system. Unfortunately for us, and even the highest trained computer technicians, fixing the blue screen of death isn't always as simple as we'd like it to be, and it can take an obscure amount of PC knowledge to get to the root of the problem.

90% registry cleaner can fix the blue screen.

http://bluescreen-fix.com/