Not long ago, I got hold of a 40GB hard disk and decided to do a WinXP/Ubuntu9 Dual Boot. I thought It would be rather simple. So I installed WinXP on it partitioning the whole thing, then I installed all my favourite software on the XP while listening to an old Floss Weekly Podcast about Wubi, which probably made me over-confident, then I got out the Ubuntu installer disk, (a while before I had downloaded the .iso form the ubuntu site and burned it onto the disk) booted onto it and tried installing it.
It was as slow as a dead donkey and crashed constantly. So after 4 or 5 tries, I gave Up and tried something else. I plugged in my WinXP hard disk jumpered it as a master and turned the 40GB into a slave.
Then after reading up, I went into XP, right clicked on my Comuter, manage, manage hard disks (or something like that) and in that I formated the 40GB hard disk as an NTFS file system.
Then I rejumpered the hard disks to what they were before and tried installing ubuntu on the 40GB, It worked perfectly and I managed to partition exactly half the disk, and got ubuntu working perfectly in about 30min.
Then I got the WinXP installer disk out, installed it and got it woking. In the end, it worked fine (untill I started fiddling around with the RAM cards!).