My advent laptop wont power up

Probably a motherboard fault have to go to the repair shop

try another charger ,,, then check the power plug ( could be broken or needs re-soldering ) .... after you try all of that and didn't work that means you need to replace the power ic ...

connect the charger to the socket, then connect the charger to your laptop. if it does not charge remove it for 5mins, connect the charger back. it will work now. sometimes when the battery is fully charged and you remove the charger and connect it back it may not charge until the battery is low;lets say 99%.

The wattage is to different, the wattage for the adapter is 90watts, and the charge for the advent is only 65w.

You can always try it, but you risk damaging your battery, or motherboard.

Its either a power problem charger or power socket on the laptop or a motherboard problem

Can get universal power supplies for about a tenner on ebay.If it wont charge but runs on mains it will prob be the battery

Check your mains adapter plug that connects into the laptop power socket with a multi-meter, the voltage should be slightly higher than the voltage that is printed on the label on the bottom of the adapter. If the voltage is zero or way below the voltage that is printed on the label then the power adapter is faulty and needs to be replaced.

If the adapter is OK then connect it to the laptop and power it up, then look at the power/battery charging LED light and wriggle the power plug in the laptop's power socket. If the power/battery LED light flashes and in a certain position this LED light stays firm, then the power socket is either faulty or it has a dry solder joint where it is connected to the motherboard.
This can be repaired but it requires the laptop to be completely dismantled to get at this power socket and repair. I suggest you get a quote first.

my laptop did this once and it turned out that the hard drive (of all things!) was at fault. it was scratched in a critical area of the O.S. that is only acceded when on battery power and so it can not start. OR it is completely unrelated and you need help from somebody else

remove the ac adapter
take the battery out
be sure nothing is connected with your laptop
then press and hold the power button for 60 secs to drain static as it is the most probable reason laptops stops working.
then connect the ac adapter only and without the battery try powering on the system
if it powers on
you can again shut it down
insert the battery
it should surely power on