Router Problem

So, last night, my Wi-Fi suddenly went out. I went to check on it, and it was making a hissing sound. Now, I know that the hissing sound is not an actual problem but ever since its been doing this, the range of the wi-fi signal has gone from 100+ feet to less than 2 feet. I tried restarting my router, my modem, and the surge breaker. But nothing seems to work.

Router: Netgear WNDR3700
Modem: ARRIS TM502G

Any help is appreciated :D