I've just installed Windows 10 Pro 64-bit onto a 7 year old PC. The PC was previously running Windows 7 Pro 32-bit and I've installed Win 10 onto a separate partition so I can still boot up Win 7 or Win 10 as required.

It was running fine for a few hours after the Win 10 installation but when I was ALT-TAb'ing between some open windows (one for Notepad, the other ESET NOD32, and another I forget) it suddenly crashed and rebooted. No BSOD, it just immediately shut down. It's never done this with Win 7, just this one instance so far with Win 10.

I've not yet been able to reproduce the fault, maybe when it happened it was just coincidence that I was using ALT-TAB at the time.

The Event Log contains the usual Error 41 that you get on a sudden unexpected shutdown.

The motherboard is an ASUS F2A55-M

Win 10 is a brand new installation, fully updated as of today.

I've not installed any separate drivers, I just let Win 10 install what it thought was required.

Any ideas please as to what I should look into ?