Tape Hardware Problem

Have been running this tape backup for a few years, consistantly backs up on a nightly basis. this morning seagate reports error running job. I notice the tape device is not registered in the seagate. I go to NT backup and it reports a tape device is detected but is not responding….
i then go to control panel tape devices and rescan, still there. then i go to devices and try to stop the 4millim device, states unable to stop, and the function to stop it is no grayed out. I have three other tape drive identical to this one in other servers.
what if any is the solution without rebooting my server?

thanks