Hi Lofty,
when a computer blue screens, if the settings are correct, a dump file will be created recording what was the basic cause etc. We need you to upload these dump files to the forum so we can read them and tell you what is wrong. In fact we have an app which makes the process easier. Please read the thread found here:
How to ask for help with a BSOD problem
If there doesn't appear to be any dump files then you'll need to change your settings so that they're created when the machine bsods.
Open the run application.
Type sysdm.cpl in the run box and click ok.
Look across the top of the system properties box for 'Advanced' and click that.
Look for 'Startup and Recovery' near the bottom and click 'settings'.
Near the bottom you'll see a drop down menu under the heading 'write debugging information'.
In the drop down menu choose ' small memory dump (256KB)'
Under 'small dump directory' make sure it says %SystemRoot%\Minidump.
Click ok and your good to go.
You will have to wait until the computer bsods again to have the dump file created but once it does use the app and upload the files.
In the meantime have you considered using system restore to return your machine to a time before it started blue screening?
Restore system files and settings