Internet Access in XP defeated by running Knoppix 6.0.1

I have a space problem in MS XP on my c drive but d and e have space and they are all on my SATA drive. I was told that Knoppix and QT Parted would probably be able to resolve this problem. I have downloaded Knoppix 6.0.1 and it runs as a live CD on boot up and accesses the SATA drive and also the internet via my network router.
Next job then is to back up my files to the other PC on the network (CD or DVD). So I remove the Knoppix cd and reboot into XP. The PC then reports that a network cable is unplugged. A new cable is tried - no change. Windows cannot now access the local network or the internet. Running Knppix again shows it CAN access the internet ok and there are no cable problems.

How can I get network and internet access again on Windows XP ? Any help would be appreciated - I am a Linux extreme novice. Thanks.

HUH! uhm, try waiting 15 min or so, there migh have been an unclean release of the DHCP lease or similar.

Thanks for reply. Not clear when to wait but have tried in XP and no change. Windows displays network disconnected Icon at right of task bar. Network card is AsusTek/Broadcom 440X 10/100 if that helps.
When running Knoppix the Router port indicator for the PC comes on about 5 secs after the start up sequence starts and goes off again during the shutdown kill sequence. Windows trouble-shooter is no help in this instance.

the troubleshooter has helped me all of 0 times so no news there.
as to knoppix working and windows not i think is VERY odd, uhm, you have a router between your computer nd internet? have you tried rebooting that? (or same if it is a DSL modem)

The router is Zyzel Prestige 600 series. I do not want to reboot as this PC, I am talking to you on, routes through it and I do not want to risk loosing any more connections. I can tell you that patching this PC on to any of the router ports lights them up. Only the port with the Knoppixed PC does not light whichever port it is plugged to. So I would think it is not due to a router problem as the "no light" firmly stays with the Knoppixed PC except when running Knoppix live CD. Any further thoughts please?

Okay a little bit more information for you guys. I have managed to get windows accessing the network again.
I have run up Knoppix from the CD. It connected as usual to the router and I was accessing the internet when it all locked up.
I reset the pc and took out the Knoppix cd ASAP. The PC rebooted into XP and the connection to the router was still lit. So I am out off trouble for now. Now I can get back to the problem of my c disc not having enough space! Partition Magic I think.

Any Linux live-cd will resize your partition using Gparted (usually in 'system tools'). Just defrag your Windows system and back-up any valuable files (although if it's the first partition it's easier as it will use free space to enlarge the partition or maybe you should care with the files in the next partition..you'll see).
Try SliTaz http://www.slitaz.org/en/ , it's only 30MB and you'll have a lightning fast linux o.s. to play around.