1995 s320 starting problem and SRS light
 

My 1995 S 320 will not start on occasions. The dash lights will come on and all other accessoriers work as well. The car will not turn over so I get out and reset the factory alarm wait then turn it back off and it still will not start. But if I wait about 5 minutes it then will start. I have checked all the wires at the starter and also the nuetral safety switch but nothing appears to be wrong. I was told it might be a relay and or the ignition switch. Can anyone help please? I really need to fix this issue as it always seems to happen when we are in a hurry.
The SRS light on the dasn stays on after starting and then goes off after 2 minutes. I know this is not right how do I find and fix this problem as well?