Limited access to wifi and more for unknown reason (laptop)

My situation is a little bit hard to explain but I'll try to tell you the best I can; about 3 days ago my father cut the power to the house too replace a bathroom light without getting electrocuted. Ever since then my laptop has been playing up in all sorts of ways, most notably the poor internet connection (hence why I put this thread in the network area because I'm not too sure what's going on with it at all).

To sum up it's problems quickly: certain things tend to take a lot of time on it. Plugging in memory sticks, opening up new Windows, even the Internet. I do know that it isn't my family's wifi that is the problem, all our other devices work and my laptop has the same trouble with my school's Internet (also because it isn't only my wifi being effected). I also know that it's not memory or CPU related.

It pretty much turned from a pretty decent laptop of it's age to the slowest computer in the world within an hour.

Anyone what the problem is, or do I need to give anymore detail?

Ok, now the Internet has fully stopped working and some apps crash when opened.