Allo bqalin
The first thing you need to do is either right-click the 'My Computer' icon then select 'Properties' or, from the Start Menu - Settings - Control Panel - System, either will bring you to the same box.
When the box appears, click the 'Advanced' tab along the top, then near the bottom of the box is an area marked 'Startup and Recovery', click the 'Settings' button. Near the bottom of the next screen is an area called 'System Failure', untick the box marked 'Automatically Restart', then OK everything back to the desktop. That will stop the PC from restarting itself, when it decides to go 'belly up'.
I Googled the Stop error code and it would appear to be one of your hardware drivers has gone weird, possibly the hard-drive controller. If you repeat the above steps, but instead of clicking the 'Advanced' tab, click the 'Hardware' tab, then the 'Device Manager button.
Check for any yellow triangles or red blobs next to any of the entries.