What did you do to uninstall the loader service.
When the meter started, did it show its normal splash screen? Did the tbbmeter.log file that is in the same folder as the exe have any entries from the time when you tried to last run it?
If tbbloaderservice.exe is present, and tbbmeter.exe is present, then from the cmd prompt try
net stop tbbloaderservice
net start tbbloaderservice
When you did a manual start, did a UAC (User Account Control) window appear?