Delete the stored network connection from the laptop and re-scan see if it sees the wireless network. If so, try reconnecting again. If the SSID is hidden you may have to set the connection up manually.
Failing that, does your laptop work when connected via ethernet? If not, do the following:
Open a command prompt.
Type "netsh int ip reset" without the quotes.
Reboot computer.
Another thing to consider is the wireless software on the laptop. Are you using Windows' Wireless Zero Configuration Utility or is it 3rd party software that controls the wireless connection? If it's third party software, uninstall it and try connecting the normal way (by letting Windows manage the wireless connection).
If none of that works, can you roll back the driver to a previous version? If you've run a custom Windows Update for example, it may have installed a "newer" generic driver over the top of your old one. I've known this to cause random problems no end of times.
If the iPhone works OK then the wireless network is OK, hence the router doesn't need to be touched. If the wired computers work, this further proves the point.
If the computer is configured to automatically acquire an IP address and it still doesn't work, it's still not a DHCP issue otherwise the iPhone wouldn't be working.
The iPhone works, so MAC address filtering is more than likely not enabled.
To me, it sounds like the problem is with the laptop. Try my suggestions above, see if it helps.
If so, I'm owed a beer token:
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Insert beer token here
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