Sony Vaio NW Notebook will not power on

Was working a couple of days ago, unplugged it so as to send it home, plugged back in and will not power on. Trying to help a friend, so information is sketchy.
Model VGN-NW240F (on front of machine) OR PCG-7184L (underneath machine)
Age-unknown
Runs Windows 7
4g ram, all stock

Using AC adapter, adapter has green light, but no lights on laptop. Battery in or out, nothing changes, will not boot, no light on what I presume is the charging symbol on front of machine.

Battery age-unknown, but suspicion original, and always used plugged in with AC adapter.

Buying a new battery seems complicated, something about BIOS update, another site says can't be used with Win 7, and can't find the battery section of Sony's site.

Could it be a battery problem? Have tried removing battery, holding power button for 45 seconds, then reassembling, nothing.

 

Try holding down the power button longer, I made that mistake this morning . (The charger is disconnected, right?)

I don't know Sony's very well, but if they are made to run with the battery disconnected, then no, it should not be the battery. Look around at the troubleshooting info at Sony (or in the manual). See if talks about running without the battery.

Matt

 

Finding information on this Sony is difficult. I can't find whether it will run without the battery, so have ordered a battery to see if that works

 

If it is the same whether the battery is in or out, I expect the battery is not the problem. It could still indicate a power problem, but the main power system (or the AC-DC control) is part of the motherboard. Changing the mobo is not easy on a laptop and the cost of replacement will probably be uneconomic.