command prompt
ipconfig /release (should release all active DHCP leases from the local machine)
ipconfig /all (should confirm that all DHCP addresses are now 0.0.0.0)
ipconfig /renew (should appropriate a new DHCP lease)
ipconfig /all (should confirm new lease address)
How long is the DHCP device leasing addresses for (you may want to adjust this time, try shorter lease times, maybe 1hour)
How large is the lease pool? Make sure, if there are computers or other network nodes (servers or printers) with static IP addresses that they have an exception created within the pool, or better yet, that they are addressed outside the scope pool.
Make sure that if the computers have multiple network adapters (wired and wireless) that...