keep losing service

I had xplornet installed last summer. The last couple of months i keep losing internet connection and i have to reset everything. i mean uplugging my modem and router, waiting a minute and then plugging them back in. i do this about 4 or 5 times a day. i had a tech out two days ago. he replaced my modem and said everything should be fine. an hour later it was out. i thought it might be our router so i sent it to dlink to be checked. they sent me back a new one. but the two weeks it was gone we still had the problem. now the router is reconnected and same. i have two pc's hooked in and one laptop in the livingroom (it is the only one on wireless). what can i do?? i should add that all of the lights are always on on the modem and all of the lights are on on the router, showing a connection. the "little" screens showing a connection is there on the bottom right hand corner of my screen, but if i log onto msn or something, it says i have no connection