Music videos knock out my router

I have a wireless linksys router 802.1.1b befw11s4 ver 4. My main computer
is connected via a wired connection. My second computer is connected via a
wireless connection. when I watch music videos on yahoo launch on my main
computer, my router is knocked out. The error (if I've tracked it down
successfully) is
The IP address lease 192.168.1.100 for the network card with network address
ooocf..... has been denied by the DHCP server 192.168.1.1 (The DHCP server
sent a DHCPNACK message)

I can watch music videos with no problems on my second computer which is
connected via wireless.

I have tried changing channels, telling my router to be "always on" and
changing the speed on my nic card to be 10mbs half duplex. My main computer
is a Gateway Media center

Any suggestions....other than don't watch music videos?

Thanks in advance

Vivian K