My Wireless Internet connection keeps disconnecting! help me please.

[Soumi]

For no reason my wireless internet connection keeps dropping out.it's really annoying because i can not watch no videos , and the download never ends! i also keep timing out when i'm playing an online game. i have tried to update the driver , disable and enable it but still not working. i'm using the internet for two desktop computers. the router isn't too far from them, i'm using a Sagem modem and a Ralink Wireless LAN Card for both. the first PC system is windows XP and the second is windows 7..
if anyone had this problem and solve it or has any ideas on this problem , please answer me!

Thanks
Soumi

 

[Soumi]

Bump help please!
by the way , i connected the modem using a cable but still the same problem , so maybe the problem is in the modem?