I am having an issue with my laptop. It is a Toshiba A105.

Here is what’s happening:

-I turn on my laptop
-It attempts to load up
-It does this for about 5-7 seconds then immediate shuts down.

Things I’ve tried:
-Made sure battery was fully charged.
-Purchased and tried two new batteries
-Purchased and tried new power cord
-Purchased and tried new power supply and power button.
-Purchase new motherboard (turned out to be the wrong one, but ordered another to try)

This problem started gradually. Sometimes it would start and stay on and other times I would have to charge for a while then it would finally come up. Now, it just will only come up for about 5-7 seconds and shut down.

Does the fan sound like its operating?
Does it stayed powered up longer when you first turn it on?

Yes, the fan runs until the laptop turns off.
It only stays powered up for about 5-7 seconds then turns off.