Is it even a Virus??

Have windows 7 and having issues with My Segate external harddrive.Its like somehow my computer is getting re infected. Makes no sense.

Run windows 7 things work ok for awhile, external harddrive no problems. Then for some reason I try to open My external I get the error message, winlogon.exe can not find specified drive.

Restore my computer with my backup, external works fine. Its like somehow my computer is getting re infected, makes no sense. Or is it something else??