Starting Trouble. PLEASE HELP

[nosignal]

First of all, I'm not a car person really. my mom's explorer has a problem that came about today. It won't start. The engine rolls over when i turn the key but just dies down after a while. My dad tried using a booster to charge the battery but it didnt make a difference. Any help would be fantastic. Thank you

[MagicRat]

There are many reasons why a vehicle does not start.
Does the turning over seem to be slower than normal, before it dies?
If yes, the battery could be going bad. In cold weather, batteries lose much of their cranking power.
Also batteries do not last forever, and often wear out after 3-5 years. Your battery may be marginal in warm weather and now that it's cold it just is not up to the job.
You can remove the battery and take it to an auto parts store like Pep Boys. They will test it for free and let you know if its weak and needs replacement. Make sure they test the battery when it is cold (outdoor temp). If they test it when it warms up inside the store, you will get a false reading.

[rhandwor]

It would help if you give the year and engine size. Also exactly what's going on with it.