They would prefer to stray away from reformatting, and are worried of losing important things.
There's no need to worry about losing important things if you back everything up properly first. In fact they should be more worried about losing important things if they're using a machine like that without any backups at all!!
Regardless, if it's really not an option (which is rather silly IMO) boot into safe mode and check if the problem is still there. If it's not, start disabling services and startup tasks one by one until you find out what's causing the issue.