Hi
qkflies
Has the process actually terminated - check with Task Manager (Ctrl/Shift/Esc).
Calibre should NOT be in Applications nor in Processes.
- If its absent from Applications but present in Processes then as Peter T has suggested, Preferences->Look and Feel->Enable System Tray icon is probably set. You need to right click Calibre's icon in the Tray (Notification area) and select Quit.
- If its absent from Applications but present in Processes AND Preferences->Look and Feel->Enable System Tray icon is NOT set, then for some reason Calibre is not quitting.
I've seen this happen occasionally with other programs - but NEVER with Calibre. Often if you wait a while (10-100secs) the program will eventually exit - it think its to do with freeing up the Heap.
Otherwise kill the process with Task Manager (right click->End Process), that should obviate the need for a reboot. But its not a viable long term solution, you'll need to find out why Calibre is not terminating normally on your system
BR