Evo n610c not charging properly? (by 3 users)

A family member just bought the laptop about 2-3 months ago, and all was well in the beginning the battery would display it had anywhere from 2-3 hours usually but would randomly power down for no reason, but when running off the ac adapter it would act fine, so just got a new battery for it a couple days ago with full charge says it should have 4 hours but today in less than an hour it did the same thing shut down with no warning, so turned it back on and the battery displays it has 4% charge (said it had 70-85% before it turned off) so now I've got 1 new battery, 1 that may have not have been bad after all, and I'm stumped though maybe it was overheating but i don't think thats the case now, drained the new battery started charging it and it stops at 29% like its full but if i unplug the power cord and plug it back in it resumes charging. Ive checked the screen saver and turned it off, adjusted power settings, so I'm about out of ideas other than charging the batteries and testing with a voltmeter as soon as i find it

1 more thing i noticed today when it shut down i was viewing a blog like page with a bunch of videos not even a min after i started the video it shut down, didn't think much of it just a random shut down but after i restarted went back to the same page started the video again and sure enough it did the same thing i don't think its only tied to vids/movies but that seems to kill it pretty quick