128 meg is amazingly little for xp pro, you would have been better off spending less on the OS and more on memory. As to Knoppix, 128 is cutting it close for KDE, the default gui. Things are even worse if this system has on-board video taking some of that memory. And we don't even know yet that the disk was burned properly (although the booting and then failing is a sign that you at least know how to burn an ISO). I would suggest that you look at the cheat codes, there is an optionto try to boot just into text mode, which will tell you if it's a gui issue or not. There are also cheat codes for less memory demanding guis than KDE if you want to try a different gui.