Ubuntu

The OP has said that the drives can be plugged into other machines and behave. If it was a virus then all other machines would be infected and none of them would behave.

Anyway, as Corona688 has already said, a virus needs to be executed to do any damage and if the drives aren't mounting (or even being seen by the hardware), no code is being read leave alone being executed.

Actually I hadntbread that bit but it just so happens there is a u3 usb that CAN execute files when plugged into a PC so go and do your homework mate

---------- Post updated at 05:06 PM ---------- Previous update was at 05:06 PM ----------

Automatically

A quick look around the web seems to say that the Dell T7500 had issues with USB ports on lower BIOS versions. Therefore, my next question is what BIOS version have you got?

If it is incompatible what's he meant to do risk rendering his PC useless by flashing a new bios

Some popular models of flash drives contain an axillary device which prompts windows to install a U3 device driver which many consider to be malware. I am hoping you understand the difference between a flash drive and a hard drive toaster, Windows and Linux, malware and virus, device driver and hardware.

Your advice of "reformat" does not help this problem, or the thread.

Well I tried to help unlike you annoying people correcting everyone

That's one option. Another would be installing a card for more USB ports, or arranging some other form of I/O like NAS.