I've just installed Windows 10 (free upgrade from Windows 7 home) on my Levovo G550 laptop. The upgrade went OK until near the end when it hit problems, first sitting with msg 'this is taking longer than usual but should complete soon' for about 45 minutes then leaving me with a blank black screen with a cursor. There appeared to be disk drive activity so I left it for several hours , eventually giving up and rebooting. Windows 10 come up but the screen started flashing after about 30 secs and flashed, totally unusable, for a couple of minutes and then stops flashing with an explorer.exe crash screen appearing saying 'the instruction at 0x00000000 referenced memory at 0x00000000.The memory could not be written.Click OK to terminate'. If I click OK the flashing starts again until it crashes again. If I leave this error box on the screen the system is perfectly usable and works fine.

So how do I get rid of the explorer.exe error ? I can't see any way of re-installing Windows 10, in fact the whole Windows Update facility seems to be missing from my control panel.

Can anyone help ?