Stop errors or BSOD are usually due to device driver problems. Have you recently updated a device driver, or windows update hardware device driver suggestion?
The BSOD screen has 3 areas, a Symbolic Error Name, a Troubleshooting area, and an Error Number and 4 parameters.
Write down the Symbolic Error Name and Error Number, to see if they are always the same, and see if you can see listed a device driver name, to give you a heads up as to what may be causing the Stop Error.
If you note a specific driver, try uninstalling, reinstalling or updating that driver.
Other helpful utilities include the Drive Verifier Manager (verifier.exe) which when turned on, will give you info as to the cause when a BSOD occurs, or try a MiniDmp Crash Analyzer which are available for download.