Passport ultra 2TB not seen by laptop

Hi
Thank you for your suggested actions to attempt to resolve my problem.
To prove the drive I connected it to a second laptop…all worked ok so localising the problem to the Laptop.
I have tried variouse things including deleting INFCACHE.1 then remounted usb devices…still seeing drive as raw. In Disk manager the drive shows up but with no drive letter. Just to see what would happen I gave the raw drive a letter…BINGO the drive changed to NTFS and showed up in file manager and I could access the drive. Still do not know why a drive letter was not allocated automatically as normal. Dismounted the drive rebooted laptop plugged drive back in ALL SHOWED UP OK AN WAS ACCESSABLE. Noted the drive letter I had manually allocated had been retained.