So, you're trying to connect with both laptops wirelessly right? I hate to ask a dumb question, but how far away are you from the wireless router, and what is the antenna range for your new laptops? If it's a range problem you could buy a range adapter to increase your range, if thats not the problem, it may be something with security restrictions you have configured. It could also be a problem with DHCP.
1.) Do the wireless laptops have built in wireless cards, or do you have pcm/cia adapters for them(cards that plug into the side).
2.) Does the new laptop behave differently if you move closer to the access point(router)?
3.) Did you set any configuration options in the router's control panel, like limits on DHCP leases etc...