01 LS just won't start

Can anybody help me???
The latest problem I'm having with my LS is that it just won't start. It started being temperamental a couple of weeks ago, now no matter how long I try, it won't start--even when jumped. It will act like its turning over the first time or two, then you can hear it just getting weak. Its latest trick is it will click a few times, then the alarm will activate and the horn starts honking. I pulled the battery cables off in an attempt to allow the theft system to reset, but this didn't help.
This car has been a pain in my neck since I got it.:banghead:

Sounds like all that's happening here is you have a weak battery. If the battery is the original, then you're certainly due for a new one. Are the cables clean and tight?

-Rod

Battery connections are clean and tight. I'm looking up batteries (since I'm stuck at home). I have a V8 sport pkg, does it matter if I go with the 650 or the 750 battery? Is there much difference besides cost?
Thank you so much for your help.

Twentysgirl, the same exact thing happenned to me and like Rod said its weak battery and it will set the alarm off also. Other than $250 at the dealer, the only place I found one is O'Reilly's Auoparts and they have the 750A and it's only $60! I replaced mine 2 months ago and it worked like a charm and was easy to install.

The wifes 01 would spin the motor just fine but wouldn't run.

Put in the expensive ford/thunderbird only battery and it fixed it.