As Don suggests deal with the relay first, sounds like the same one you had replaced before, common problem but a new one should last more than a year. After that do some basic diagnostics, do you have spark at plugs, does tach nudge up slightly as you crank? If yes to both then problem is almost certainly fuel related. Bad fuel pump maybe. Post results, do you have tools, maybe we can walk you through?
I would not recommend a dealer for this, try to locate a reputable Volvo service garage.