First off, I was not aware that port forwarding would do anything as far as speed , other than specify which computer the packets are to be sent to wich box, in case on a VPN , of ftp, or gaming ect.
 You have DSL, so you need to make sure the modem is in bridge mode and DHCP is on unless you have another router that is set up to lease ip's,(in this case turn off DHCP server ), then release and renew all dhcp.
  With my knowledge, the only way that other machines on the network will not connect to internet unless this one is on, would be if you had it set up as host and all others to connect through it.

Sorry, I guess I should have been more clear. We just upgraded to FIOS with Verizon. I followed the instructions on Portforward.com to do the forwarding. Now it seems that the other pcs on the network are being routed (?) thru the laptop to get out to the web, and unless it's turned on they can't connect. Does that make any sense at all??