This laptop wasn't getting a good connection between the power adapter and the receptacle so I took it apart to see if there were any bad solders etc.
I did so and also cleaned the fan, then put it back together and now it won't turn on at all and the LEDs to indicate charge won't light up. I can put my multimeter on the solder points of the receptacle and it does read the correct voltage.
I have already tried removing battery and holding down power button.
You took it apart, so something either got damaged during the process or not connected properly when you put it back together. Nothing we can see from here, you need to check over the system or have another local tech look at it.