The internet stopped working? I'd personally blame anything but Steam in this instance.
If you're working on a wired connection it could possibly be the ports, the card, the cable, the router...
Wireless, it could be the card, a dongle you might be using, the router, the cables going from the router to the internets...
I have never had a problem with Steam killing my internet either. If you're nervous about it, I say go ahead and make the jump. Trying to play Munch is better than not playing at all.
