1996 Volkswagen Golf car won't start

Electrical problem
1996 Volkswagen Golf 4 cyl Manual 155, 00 miles

within the last 2 wks. My car was beginning to become hard to start I thought it was the battery, so I tried to replace it and the alarm system went off, my daughters fiance disconnected the alarm module and cut the starter wires that was suppose to keep my car starting and twisted them together. Then the car wouldn't start. Found out that the starter was bad, replaced it. The car finally started and had turned it off and on at least 4 times that night just fine, only to go out the next morning and it wouldn't do anything. The car has a humming noise coming from the fuel injector, so don't think there is anything wrong there, but don't seem to be getting any ground to my solenoid. Can my ignition switch be the problem? Or did I do something wrong when I let him disconnect the alarm system? Can you please help