Did you try the air filter to see if it's clogged? It doesn't happen a lot, but it is possible, since it's easily overlooked.

How many miles on this car, and what's been done, maintenance-wise, in the last 20,000 miles or so? Do you take it to a mechanic for maintenance, or do you do it all yourself?

It could be any of the following in the fuel system alone......starting from the back; in-tank sock (if the car runs on a full tank, but quits when the tank gets down to half-full, it could be the in-tank pump), fuel filter, external fuel pump, fuel pump relay. The fuel pump relay is a story (with lots of scanned pictures!!) in itself.

There are also two fuses which determine whether the FP relay will work. You might look at the fuse panel and see if the fuses are corroded at the ends. Sometimes just turning them in place can make them reconnect, and your car might magically start and run. Just run your finger across them and spin them and see if the car will run. If you decide to clean the fuse panel, disconnect the negative cable of the battery first, so you don't spark anything, and then clean remove the fuses and clean the terminals with an abrasive. A scotchbrite pad will work, or steel wool, or light sandpaper, or a wire brush. Again, disconnect the battery first so you won't have to replace the ECU because you made a spark. And while you're there, make sure that your fuses are good. You might test them with a continuity tester or test light.

If you're determined to sort this out yourself, a Bentley manual (about $50) is a great place to start. Amazon.com or bn.com will have them. Or you might find a used one on e-bay. It doesn't have absolutely everything in it, but it comes close, and it has troubleshooting charts.

Otherwise, you might be well-off to take it to a mechanic who knows Volvos. You can always get a second opinion here.