Lumina Doesn't start sometimes

This started a couple of weeks ago. I scanned thru forums and googled this and it seems like this happens with GM cars 10 years and older. I replaced the battery and the problem went away for about a week. I was leaving the grocery store today when the security light stayed on. I waited about 10 min till the light went off. turned the key and it engaged. Will changing out the lock cylinder do the trick?

Things I've already done:

1. Battery cables ok
2. New Battery
3. Alternator checked out ok at Autozone

Figured it out! Thanks guys! :p