Wifi Connection interfering with cordless frequency??

My internet connection (through wifi) has been acting weird. It disconnects suddenly and reconnects after a few seconds. I use a Dell Inspiron laptop. I think the laptop’s wifi connection has been interfering with cordless frequency. That’s why it gets disconnected and reconnects itself after a few seconds. I changed the channels from the router settings…but it didn’t work. I was wondering if there is anything else I could do to help prevent this problem. I never had this problem with this laptop before. It is only recently that this has started causing problems. The other laptop, I have at home, works fine and I never encountered any such problem.
Im running windows vista and the dell wireless 1390 WLAN Mini-Card Rev 3.6.
Thanks.