I use a Samsung i5 (I think, I'm nowhere near the box to check specifics) laptop purchased summer of last year, running Windows 7 with a Quad core and AMD Radeon graphics. I'm pretty gentle with it, and leave it plugged in while using intensive programs, but within the last month my battery life has been strange. It would normally run down to 15%, give a warning, and shut off by 10 if I hadn't plugged in. Now I get about 37% and no warning- I've been exceedingly glad of Word's backup feature.
As a matter of course, it's always run a bit warm and I keep the vent clear, so I don't think it's overheating (I've been vigilant, having two pets). It's also set to Power Saver when unplugged with the lowest brightness settings, so I should have about 3 hours of battery life.
Any help much appreciated. I figured it'd be best to ask around before calling in my warranty.