BleepingComputer.com: Please help think this is hardware but not sure

so a good friend of mine is letting me check out her computer. from her discription (which i will post) it sounds like a hardware issue. i was just hoping that you guys could help me out, so i can tell her exactly what is wrong and then help her fix it for less than those over priced computer shops. thanks so much (in advanced) her is exactly what she told me.
"well it's hand-me-down and i got it for free from my cousin because it has a few problems. right now the issue is that it doesn't like to turn on all the way. like it's on, but the little "disk activity" light or whatever is off. then it turns itself off and on again over and over again. sometimes the fan comes on for like a second or two, but then... Read More the thing shuts down again. normally it only does this a few times, the most (before now) ever being 40 minutes. i've been trying to turn it on for 3 days now for several hours at a time and no dice "

i will post more when i get to look at it. if you guys have any idea on how to help it would be greatly appreciated. i already have UBCD (ultimate boot cd) which i think will be my first approach.
thanks so much
Josh

From what you have said so far my first thought is the power supply.

When you get the unit open it.
If it has a Bestec power supply, or is a HP/Compaq quit trying to start it.
[HP/Compaq use rebranded "bestec" .

Post the brand of the power supply.

Thank you for the quick response i will post as soon as i get my hands on the unit. thank you.

Try replacing the battery on the motherboard first as it may be dead from old age, good luck.....

Its a laptop its not going to have a Bestec power supply. Trying to locate the cmos battery on a laptop is not an easy task. The first thing I would do is take the brick and check the output with a voltohmeter to be sure its not faulty. If the AC adapter test out ok remove the battery from the laptop and plug it in to see if it turns on. If you still get nothing its definatly a power issue. It could be a DC input board, the DC input jack, or a bad motherboard. Please post back with the make and model of the laptop.