A shutdown problem is most likely due to overheating, usually caused by dust buildup inside the case, and around the heatsink fan. I recommend that you try to remove dust somehow. The best way is to remove the top or bottom housing and blowing air [buy compressed air can] around the mobo and heatsink/fan from the inside, but this isn't easy to do for novices. A decent alternative way is to blow air [not too close] to the side vent, which should blow air outward on the bottom fan/heatsink exhaust, and other open areas around the casing. Just make sure battery is removed, and the unit is completely off before doing so. See if this changes the time the unit stays on.
If removing air doesn't fix shutdown issue, it is a faulty hardware [can be anything], related to overheating or serious power related failure, such as bad battery or adapter. Overheat issue will result in unit turning on, but shuts down after about the same time [i.e. 15 sec].
Power issue is usually not consistent [i.e. power turns on once, doesn't work again, or jiggling the adapter connector works on and off]. In many cases, adapter connector to the dc jack isn't secure due to some sort of physical damage, which means both the adapter and dc jack may need to be replaced. A way to find out which is faulty is by replacing the battery or adapter, it would be best if someone has a similar brand laptop, so that you can try to see if the battery and adapter are interchangeable, so you can test out yours [try charging battery] and vice versa.
If all else fails, take it to a repair shop, and get an estimate. If the unit's value is low, I would sell it on ebay as is. As long as the mobo is good, people will buy it.
If removing air doesn't fix shutdown issue, it is a faulty hardware [can be anything], related to overheating or serious power related failure, such as bad battery or adapter. Overheat issue will result in unit turning on, but shuts down after about the same time [i.e. 15 sec].
Power issue is usually not consistent [i.e. power turns on once, doesn't work again, or jiggling the adapter connector works on and off]. In many cases, adapter connector to the dc jack isn't secure due to some sort of physical damage, which means both the adapter and dc jack may need to be replaced. A way to find out which is faulty is by replacing the battery or adapter, it would be best if someone has a similar brand laptop, so that you can try to see if the battery and adapter are interchangeable, so you can test out yours [try charging battery] and vice versa.
If all else fails, take it to a repair shop, and get an estimate. If the unit's value is low, I would sell it on ebay as is. As long as the mobo is good, people will buy it.