Just got my computer back and hooked up to my modem...didn't have to install anything again?

Alright, this may be a stupid question..but I've never done this before. I have had the same internet service provider for 7 months and two weeks ago I had to go get my computers memory completely erased. When I finally brought my computer back home and hooked it up to the modem, it worked without a problem. I didn't have to install anything and didn't have to go through any network connection detections through my computer? Does that sound right?