This could be several things. Boot into safe mode (if possible) and see if it ejects. That would tell us if it is a driver and service problem. From safe mode, disable the BEWS and BESR services and boot into normal mode. If it still ejects, then I would guess that it is a driver issue. You might want to approach HP and see if this is a known issue with a solution. If you used the RestoreAnywhere feature in the recovery disk, it is possible that a driver reinstall occured.
There is a 'tracer.exe' utility in the Backup Exec folder in Program Files. That will output a .bin file. If you private message me with that file attached, I can have someone take a look at that and see if this is related.