Hi,
My son's computer won't start up, so I removed the HDD and have plugged it into mine using a USB 3.0 to IDE/SATA cable. I'd normally make more effort before taking the HDD out, but I wanted to try the USB-->SATA cable out.
I was expecting to see some kind of corruption, but everything looks okay: just from File manager, disk management, and a Malwarebytes scan (which it's still doing, 1 hr 28 mins later..

)
In Command Prompt, it was coming up with some kind of driver error and the Windows 7 disk didn't really help. The BIOS looks different to what I'm used to: you can use the mouse and everything
The Win7 disk contents appeared in an X drive, and C seemed to have nothing in it: but the 177/232 GB looks okay on here..
The PC is an old Dell: one of 2 we picked up in an auction ~ 3 yrs ago. Dell Optiplex 780 (pretty sure it's the DT (DeskTop) ). OS is Win7 64 bit.
I'll check what the error was (can't right now: think son took a pic. Yes I know I should've paid more attention before I extracted the HDD

) in case I can put the necessary files on it whilst it's plugged into mine, but my main reason for posting is:
What tools can I use to check it's not the HDD before I put it back in the Dell case?
Any recommended checks/scans/programs? (I've got a few, such as CCleaner, but they only seem to want to run on the main/master HDD..)
I have a couple of other old HDDs lying around, so exactly how to go about giving them a thorough checkover would be useful to know.
TIA
^..^