empty coolant w/engine light?

[JSH]

my wife went to work this morning and the enginelight came on, she drove home afterwards still on. I check the gas cap first, the all hoses and belts, then all fluid levels, I noticed the coolant reservoir is empty (sunday when we changed the oil the power steering fluid was bone dry). I picked up some prestone "works w/all colors" coolant and poured it in (i put too much), drove the car around the block for about 5-10 min and the light stayed on the whole time. will it go off on it's own? do I really have to take it to a mechanic to figure out whats wrong? how can you check for a code w/out paying the absorbatent price they ask @ the shop?

[CREWZIN]

To check the codes stored in the computer, use this link:

How to retrieve fault codes.

To clear the codes, take the negative battery cable off for about 5 minutes.