After a DHCP / DNS failure we have had several issues with particular client machines.
Although an ipconfig on the client shows our primary DNS, when I run an nslookup on any external site (lets say google.com) I received the following error in the command prompt:
"Query refused DNS request timed out..."
The machine is hitting the primary first however is getting refused, this is running as the current user with non admin rights.
Interestingly though; if I run Internet Explorer as local admin (Run As) instead of the current user everything works just fine (both Intranet and Internet.)