Do you know what type of injection your car has? Is it CIS with a fuel distributor, or the older type with a mechanical pump mounted on the engine?
Regardless of the type, though, as a first step, you should drain the tank and put some fresh gas in it. Then you should disconnect a fuel line near the engine, run it into a container, and run the pump for at least 30 seconds to purge the old gas from the system. You should get a liter or so of fuel. If not, you need to change the filter element, clean the tank strainer, look for blockage in the fuel lines, etc. until you figure out why you are not getting fuel.
Once you have fuel to the engine, check for spark by pulling a plug wire off and holding it (use insulated pliers) an inch away from the block while someone cranks the engine. If you have spark, try a little starter fluid in the air intake while cranking the engine and hope for the best.
There are posts on the Vintage Forum detailing David Speed's efforts to get a similar car running after a five-year storage.
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe