My sister tries to experiment in different ways so try to dual boot install ubuntu using the CD she burnt and she was resizing the partitions and we had a power cut which switched of the computer and once she had put it back on windows failed to boot and the only way we can access the internet now is using the ubuntu CD and testing it without any changes to the computer. We can still access the memory and now we cannot install ubuntu without deleting Windows XP Professional which took up half the memory last time and now takes up all the 70GB memory. When I try to start up the computer without using the ubuntu CD it only comes up with a flashing underscore can anyone help?

resizing? Always research a plan before you execute it. If you want to recovery xp do a repair install of xp. google repair install so you have the step by step. Flashing cursor indicated no master boot record. What you describe for your sisters operations added disk corruption to the mix. See if a xp repair install will fix it or just wipe the disk and start fresh.

so I need to get the windows xp cd and go repair install it?