1999 Buick Regal wont start

That's a voltage loss problem somewhere. First test the battery to see if it's fully charged. If so, check all the cable connections at both ends.

You need to test the battery, not just charge it. Find out if it's holding a charge.

I'd have to double check that the battery has a full charge and all battery connections, coming and going are clean and tight on all ends.

The purple wire at the starter solenoid S terminal, should have good voltage with key in the crank position, if it isn't hot, backtrack the circuit. Check circuits at crank relay. Any testing, make sure the tranny is in park or neutral and the e-brake is set.

Possibly a faulty starter? Some of the name brand autostores will test the starter for you, if you take it off and take it to them. Another possibility is your security system, but, I wouldn't think that would effect you dash lites?

I kinda doubt we have a starter issue here with those symptoms.