|"returns wrong ip address range"|
I assume you mean it does obtain an IP. I also make a big assumption that the IP is NOT an APIPA. It must therefor be getting an IP from another dhcp. If APIPA then it is not getting any IP from DHCP. Check lease times.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10