[G-spec]

this used to happen on my windows xp every once in a while

the problem always was my network adapter drivers got taken out.

network adapter is the part of your motherboard where you plug your internet cable into, and a driver is necessary for it to work.
I would highly recommend you go into your Device Manager and check if you got one of those yellow exclamation marks next to your network adapter.

I typically would end up fixing the problem by reinstalling the drivers from my motherboards official webpage download section