How do I remove the default OS from a dual boot?

[Parm]

Here's my scenario; my PC has a 120GB hard disk as the main drive. The drive was originally formatted with Windows XP, I then made the default partition smaller, added a second partition and installed Vista on it as a dual boot.

I've been using Vista for a while now and am very happy with it and would like to remove the XP install, format the partition and extend the Vista partition to the full size of the disc. How do I go about doing that?

When I attempt to format the XP partition, it won't allow me to do so as it is a system drive.

[SiM]

Not the optimal solution, but you can load a live linux distribution and then do it from there

[GoNz0]

u need the partition tools on hirens boot cd. wipe out the offending partition, expand yours and rebuild the master boot record & system drive, it will default it to the vista drive as its the only one it see's.

otherwise unhide protected operating system files and get boot.ini from c:\ open it with notepad and remove from
[operating systems] the xp boot path that will look like

multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /usepmtimer

once thats gone it should boot straight to vista.