I can't test it because I'm on a work computer and dont have privilages but try looking here...
Open resource hacker and browse to "C:\Windows\en-US\explorer.exe.mui"
In the tree goto /String Table/34/1033
*Line 533, "Start"
Edit this to what you want it to be and hit "Compile Script"....
Back to the tree goto /String Table/38/1033
Line 595, "Start"
Edit this line also and hit "Compile Script"...
Save the file, backup and replace the existing and restart.
Again like I said, I'm on a work computer and cannot test but this is more than likely where its located. Not sure which one controls the tooltip though.