This is probably the question that I hate the most. Here is what I always do to find out what’s going on: Setup the IP network by hand. In other words: don’t use the DHCP Server, at all. Configure all the necessary things in the network settings of your client machine and don’t set “Obtain an IP address from a DHCP server”. If you have done this and your network still isn’t working there is something very basic wrong, already. There is no hope that the DHCP server is going to help you to solve this problem.
Once you have a configuration running, where your two or more computers are setup using manually assigned IP addresses, check your dhcpsrv.ini file once more to make sure that everything that you entered manually appears in the dhcpsrv.ini file. After that, set the “Obtain an IP address from a DHCP server” in the network settings and reboot. If it’s not getting an IP address assigned, you need to compare the IP configuration of the manually configured with the automatically configured system. You can use the ipconfig/winipcfg tools. There has to be a difference! If you found that: try to manipulate the dhcpsrv.ini to let the server assign that option that was different in the two configurations.
If it still doesn’t work then please check your security settings. Especially with Windows Vista it is very likely that you need to open the security settings of your firewall and allow the DHCP server to communicate. Open up ports 67 https://puttygen.in , 68 and 53.
If all this didn’t help, then enable the trace (set Trace=1 in the [Settings] section) and send me the dhcpsrv.ini and dhcpsrv.trc files.