my 2000Volvo ran out of gas.put gas in it an it still wont start.what 2 do?

If it has not started on it own within a resonable time of cranking (a few minutes) better relent and have it towed to a shop for diagnosis. No need in wearing out stater motor cranking constantly. No safe way to advise here what to do verify fuel pump operation.

look for black rubber cap on the injector fuel line, take cap off and bleed the line of air while starting, until only gas comes out. otherwise check filter could be clogged.