Problem is as follows:

The PC has two options to connect to the Internet: LAN (through router etc etc) and dial-up. On either option, it connects, but cannot/will not browse.

To make matters even more interesting, the PC's DHCP client is not working - when connected to a LAN it automatically assigns itself a 169.xx.xx.xx address, with a class B subnet mask (255.255.0.0). Our DHCP server is configured to assign class C (3x255) addresses, in the 192.168.0.x range.

Windows repair didn't help. The OS is windows XP professional.

Thanks in advance.

That IP address is an APIPA (anonymous private IP address) address. Your computer will get one of these addresses by default if it fails to get an IP from DHCP (in Windows XP, anyway).

What made you decide that it is the PCs DHCP client that's not working? 9 times out of 10, the problem is a misconfiguration on the DHCP server, or a connectivity issue.

Ping your loopback: ping 127.0.0.1

That should work.

Generally, you'll get the APIPA if you have a cable plugged in and the cable is bad or the connection itself is bad.

Check your TCP/IP stack to verify that Internet Protocol (TCP/IP) is set to DHCP and your Alternative Configuration (APIPA) is blank.

Or from a command prompt run: Ipconfig /all and post that back here. Or just PM it to me because I'm not sure when I'll get back to reading this thread. Might take a few days.