yaelazz,
Put everything like it should be...
wall > isp modem/router > wireless router(if any) > wired/wireless
Power off your ISP modem/router and your wireless router(if any) for 30 seconds. Then power on the ISP modem/router. Wait 15 seconds, then power on the wireless router(if any)
Restart the computer and try to connect.
What happens?
Rick