Hi Thank you both for your replies.  I tested my drives and other hardware, everything checked out.  In the end I solved the problem by following the Dell guide on how to do a clean install of Windows 10.  I downloaded Win10 through Dell and used it to wipe all the partitions on the new drive.  I installed Windows and everything is working well.
Hi My Dad's Inspiron 3670 started having graphics problems a few weeks ago so Dell replaced the motherboard.  The engineer recommended an upgrade to an M.2 drive while he was doing the work because it ran quite slow, we had a quick look on Amazon and found something compatible and I ordered it when the engineer left. I fitted the M.2 drive (Crucial P5 Plus CT500P5PSSD8 500GB) and booted into Windows without any problems.  I used Macrium Reflect to clone all the original partitions from the 1TB HDD to the M.2 drive. I updated my boot order in the BIOS and everything started up and was running great on the new drive. My Dad used the PC for a few days and loved that it was no longer having graphics problems and was now really fast thanks to the M.2 drive but then a few days later he started getting errors.  The Recycle Bin became corrupted, Explorer.eve complained that the 'instruction at 0x00007FFDOF23EE27 referenced memory at....    and the start menu would no longer open.  I right clicked on the start menu and used that menu to shutdown.  When I restarted, Windows would no longer boot, it tried to repair itself but failed. I had created a recovery drive before started the M.2 install so I inserted the USB and recovered from a drive but that failed. I tried using Support Assist to restore but that failed and when I tried again I just got a blue screen and Support Assist wouldn't start. Nothing seems to be working.   In Boot options I only have UEFI: CT500P5PSSD8 under UEFI Boot, I don't know where my 1TB HDD has gone. If I boot into the SSD then I get a blue screen titled 'Recovery' it tells me a required device isn't connected or cant be accessed, if I select F1 to enter Recovery Environment then the PC shutdown and returns to the same screen on boot. I've built PCs in the past and used to mess around with Windows XP and 7 a lot to get multiple OS's on them but its been a few years since I played around with anything like that and I haven't worked with a Dell PC or Windows 10 boot options before. Any ideas? Thanks
Inspiron 3670 won't boot into Windows after a motherboard and M.2 drive upgrade