configure the router to use a different Internal IP range... like 192.168.2.0 eliminating any potential conflict.
ensure you are using a crossover cable to connect the computers together, since your laptop may not have a new enough ethernet card in it to automatically make that conversion. Some will insist that all NICs since 2000 are auto-sensing, but this doesn't actually prove to be the case in every instance. Of course, you can test this yourself, by manually setting the ethernet cards in both the laptop and desktop to an internal IP address in the same range, and see if you can swap files. If you can, you don't need a crossover cable.
But, a simple alternative to ICS, is a router.
The Microsoft article that is supposed to allow for a registry setting change, doesn't actually apply to Windows XP and above. But, apparently it's simpler to alter the range. Once it is set up, go into the TCP/IP settings of the network adapter that is now supposed to be the gateway for ICS. It's IP address has been manually set to 192.168.0.1 Just change this to whatver range you want... say 192.168.2.1 DHCP won't work, but then you just manually set the address on the Win7 computer to be 192.168.2.2