Windows 7 Diagnostic Utility
If you suspect that your computer has a memory issue, but it’s not being detected automatically, it’s best to make use of the Windows Memory Diagnostics utility that’s built-in to Windows 7.
To access it:, Click Start, and in the Search Box type mdsched.exe. You can then either hit the Enter key or click the mdsched icon that appears in the search results above.
The window that pops up will ask you if you want to run the memory diagnostic now or when you next restart your computer. Make sure if you choose to run it now that all of your work has been saved first.