The quickest and easiest way in windows 7 is to use the built-in memory diagnostic.
1.Click Start or press the Windows key
2.Type mdsched.exe
3.Chose one of the available options.

If you choose the second option, the scan will start the next time you boot the computer. If you choose the first option, the computer will reboot and start the scan immediately

Or right after BIOS before windows starts, push F8, Select Memory Test from the options and run the long test, it’ll take a long time.

To do a disc check right click on c drive and choose properties then click tools and check now.