no power/battery

my car sat for 2 week while i was in mexico i started it this morning and it ran fine i went out a noon and i had no power at all i brought the battery to canadian tire and they tested it and it was fully charged i put it back in and nothing i checked the fuses and they are fine i stating to dislike my car it still desn't get warm also mabe i should get full insurence coverage and let the snow plow bump it.

I never fixed a car by using a snow plow. I'll must try that someday.

Seriously, check your battery cables for corrosion, and make sure they are tight. Then follow the current. Get a meter on the starter and check you fusable links. Then check the ignition switch. Good luck.

i had the car running when i disconnected the postive post it stopped running could it be the alternator

Most new cars will not run when you disconnect the battery. Cavaliers will not run when you disconnect the battery. Autozone will test your alternator for free. However you need test things in an orderly fashion. Follow the current from the battery.

i put on a new alternater but i cant' get my belt back on is there a trick to going it

Did you test the old one?

You need to move the tensioner. It is on a spring so you just move it around with a wrench, slip the belt on and release the tensioner. EASY.