Electrical Problems - HELP!

About a month ago I replaced my battery in my '00 Alero. In the last week (about twice) when I've been driving my lights on my dashboard were flickering like crazy and would stop when i would put on my brakes. Today my car started fine, I drove about 5 miles on the highway, stopped at a gas station, restarted my car and while pulling out it died. I attempted to restart it but there was absolutely no power. Any ideas???

Welcome to AF.

Check the battery cables at positive and negative connections and make sure they are tight and have no corrosion. Also, the alternator may not be working properly and needs to be checked out.

Well, if you want my 2 cents i will have to say alternator as stated by Bnaylor
(BOB).

I had a problem with my lights going out like that and while it sounds like the alternator it was not. The negative connection to the battery was not tight and had been arcing so the battery connection was all burnt and not getting a good connection after that. That would be my first check. The person who installed the battery might have done it wrong.