Sounds like a data collision. Is the laptop picking up an IP address automatically from DHCP? Or is it set manually for some reason?
Basically a data collision occurs when a device (the laptop) gets turned on and insists on using an IP address that another device might already be using. Then the router has trouble figuring out where the data is coming from and going to, normally brings networks to a grinding halt.
To find out if this is the issue, start the laptop, go to control panel, networking settings and go to the properties page for the wireless adaptor (I don't use windows much so this is all from memory). If there's an IP address already listed, like 192.168.1.15 for example, tick the "Get IP address automatically / DHCP" box and restart. Should fix it.
If it's already getting it manually, check your other devices. If they're all getting IPs automatically, then I have no idea.