Why is my computer's internet going out?

Alright I just recently moved out of my grandparent's house, within the past 3 months. And since then my computer's internet has been acting up. I moved into a place with a friend of mine where his laptop has 3/4-4/4 bars of internet all the time. My computer on the other hand has 2/4 or sometimes it even reads the internet as having 5 bars and typically I get 2 or 3 of 5 at that point. Me and him both play WoW and other online games and it's beginning to be a problem. I constantly disconnect. I haven't taken the computer in to anyplace yet because I'm unsure of if that would even be of help. I've thought that the issue may be in with my wireless internet card, or there may be some files slowing down my computer and internet alike. But I'm not sure which is why I'm posting on here. I'm also curious as to what the consequences of doing a full system restore would be outside of losing all my music and current files. I'm not fully sure what is done on my computer while I'm at work or out either. So people may be on unsafe websites but I'm not sure because obviously I'm not here. Thanks for any help!