Low wifi signal after cleaning laptop

[Down__]

I've cleaned my laptop (Samsung R540) and now I can't connect it to my router because the signal is too low. My other devices work well on the same wifi. I've messed up the CPU with thermal paste and cleaned it as good as I can but it was still dirty. Could it be the source of my problem?

 

[ffg7]

as you opened the laptop to mess around the cpu, you disconnected 1 or both wires that are the antenna for the wifi card. 1 is black & the other is white or light gray, reconnect both of them.