External drive inaccessible since plugged into different PC

[tinfoilzombie]

Hi,

I have a drive that was in a previous PC. I put it into an external enclosure recently and have been using it to backup some files from my laptop. I filled the drive - there is probably 2GB free - and then plugged it into my Win 7 HP desktop.

Windows seemed to recognise it OK, and at first I was able to browse the files on the drive - but after less than 30s I got an error message. I can't remember 100% what it said but I think it was that the drive needed to be formatted. The drive immediately became unreadable. I wasn't deleting or moving files, just having an initial look in folders.

Now I can't get into it at all.

Right click -> Properties -> Tools -> Error Checking says it can't be performed because Windows can't access the disk

Chkdsk says Unable to determine volume version and state

TestDisk seems to get somewhere but when I try to list the files on the drive, it says Can't open filesystem. File system seems damaged.

I can only think that some conflict happened when I plugged it into my PC - maybe due to AV software.

I'm not sure what my options are at this stage. If you have any ideas of what I could try, I'd appreciate it.

Thanks,

tfz