Serious DNS problem

Okay.. Serious DNS problem.

I have to fix a laptop wich can't connect to the internet. It can however access skype.
Ping showed that it got reply from IP addresses but not host names, i.e. it a DNS problem.

but the strange part is this..

I've litteraly tried everything with this computer.
/flushdns, netsh, host file, different DNS servers (OpenDNS, Google DNS, different ISP's), restoring system, re-installing ethernet drivers, trying safe mode, malware/rootkit scanning(mbam, G Data boot cd, emisoft anti-malware, etc.), removers(conficker, Vundo, Blaster, TDSS,), even tried wireshark and filemon from sysinternals.

am I missing anyhing here og is it possible it's a brand new rootkit which has escaped my scans?

any help would be appreciated.

The system is XP pro SP3 on a Lenovo x200