Can I uninstall 8.04 from inside windows xp

I installed ubuntu 8.04 inside windows xp with a new cd, I got somewhere past creating a new partition and was well on my way, when a message came up and said my dvd reader was dirty and could not proceed any further with the installation, so I stopped it, I restarted everything from start again from the live cd 8.04.

This time I got as far as creating the partition of the hard drive but realized that the hard drive area for installing was much smaller and the windows patition was much bigger that ever. I am guessing that ubuntu is in there some where taking up all that space, but I can NOT get into ubuntu from the load up page.
I t does not let me go past the grub page. I am only able to start and run XP with very little hard drive space left. I want to and have before used a dual boot on a different computer. I want to do it with this one but I have no hard drive space left as is , I need to get 8.04 out of XP anbd reinstall if possible without reinstalling windows all together.