1997 gmc serria truck not starting (no spark)

hi my 1997 gmc serria 4.3 v6 does not wanna start, it started about a mouth ago just fine, but it was siting for about a mouth and i went to start it and it just keeps turning over and never starts, i took the rotor cap off and clean the points but it still dont start, i checked to see if voltage was going to the spark plugs and its not so its something to do with the ecetrical system,.... anyone no whatt it could be or what to check for? thanks

I had this copied from another website, might try it and see if it helps:

These cars have what is called a PASS1 security system. If your security light is on when the problem happens, this procedure will help the system "relearn":

1. Turn the key into the on position and wait ten minutes. The security light will turn off.

2. Cycle the ignition from ON to OFF and back to ON (try not to take more then 5 seconds).

3. Wait another 10 minutes and the security light will again turn off.

4. Repeat steps 2 and 3, for a total wait time of 30 minutes. Your car's security system will be reset and the problem should go away.

Typically, this procedure is done when a body/repair shop installs a new steering column, but sometimes having the battery disconnected for a period of time will cause issues.