money sink

i have a 93 G20 which has run beautifully for the last 3 years. but for the last 2 months it has been giving this intermittent starting trouble where it just does not start sometimes. the workshop replaced the fuel pump saying it was the issue ($450) and it worked fine for 2 weeks and then again started stopping. now the workshop says that the starter is fine but the alarm light does not go off sometimes and that is what is preventing the car from starting.

the car will start without a problem sometimes and then just not budge on other days. there is no engine turnover, no clicks from the starter, the dash lights go on, the doors lock when the key is turned, and the auto belts work.

the workshop guy is trying to figure out how to disable the factory installed alarm but has been unsuccessful. he says taking it to the dealer will be very expensive. Please suggest something... i do not mind disabling the alarm completely.