Problems with router and signal strength

hello, we have cable internet service, we also have a wireless router. we have 2 computers on a network. the problem is, the internet pops on and off several times daily. i have had techs from comcast here, they have boosted the signal, to no avail. what can i try...we have switched the modems, how long do touters last, should the primary computer be jacked into the router? grrrrr, i'm soooo aggravated with this junk. thanks