Bluetooth is not part of any startup procedure, you must have turned it on yourself, so it should be as simple to just quit the Bluetooth utlity that's running.
As far as any other processes are concerned, they are there for a reason and most are owned by root. Aside from the fact that many of the obscure processes use very little on no CPU or memory resources it's a non issue. Oh, and don't mess with root's processes. Most are needed to run the system.
If any of the USER processes go haywire, then you have three options.
1. Force Quit the app if it is an app. (most will be)
2. Try killing the process in ProcessViewer
3. Do it in the terminal...
Get the Process ID (PID) number by using the ps -aux command.
Then use: kill PID if that does not work, try:
kill -9 PID
see: the built in unix manual for more info...
If all else fails....reboot!