I don't know much about wireless per se but I have a lot of general troubleshooting experience. The first thing I'd want to know would be whether the "wireless box" (router?) is receiving a signal from the cable and just failing to pass it along, or whether it's the cable signal itself that's failed. Is there a way you can unplug the cable from the wireless box and plug it into a computer?

If the problem appeared to be with the router itself rather than with the cable or the cable service, I'd want to try a different router on the same cable to see what difference that made. Any way you can borrow one? If you suspect it's the router and there's a pretty good chance you'll need to replace it anyway, you could even buy a replacement and plan on keeping it for a spare if you don't need it this time around. Amazon lists lots of routers for around $50, a few for much less. I keep a whole spare computer.