Volvo Repair: volvo 240 dl wont start, volvo 240 dl, mass air flow sensor

Question
i have a 1987 volvo 240 dl and recently (3 days ago) had the car worked on.  i had brake pads replaced and had the mass air flow sensor replaced too.  the car functioned fine for the thursday, friday, and saturday except that it idled more roughly than it had when i turned it in to get it worked on. but sunday i tried to leave and the car started, idled and died.  now it will not start and so far i have tried to jump it, put gas in it in case the guage was wrong and tried reconecting the oxygen sensor again in case it became loose.  any ideas...?

Answer
i need to know if you have spark. first and foremost. next i would replace the fuel pump relay, you can do this yourself. get the part from a volvo dealer, and they can show you where it goes. its in the car, passenger side, front of the foot well area. pull the insulation matting back and you should see a white relay.
the other thing to check, and your vintage might not have this, would be a fuse under the hood located on the drivers fender area right close to the battery. there MAY be a 25Amp fuse. if so check the fuse, as well check to see if the wires are not corroded away in the conntector.