I run 6.5.5.DND/DHCP

Less than a week ago we changed from AT&T to Sprint for our internet ISP.
I entered two DNS resolution servers from sprint into my inetcfg (DNS
Resolver) configuration. We own our own class "C" range so I had sprint
start advertising our pivately owned class "C". Today we had a problem
resolving names to ip (connecting through a browser) on most of the sites
today. Tracerts went fine (number wise), took a lot longer than usual but
when I tried to do nslookup's this is what I got:

C:>nslookup www.ibm.com
Server: Server.my.domain.com

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to Server.my.domain.com timed-out

What could be causing my DNS server to not send the request to the outside
sprint dns resolvers?

Any help would be appreciated - RJM