Can anyone help me please?

I installed Office 2003 on my computer and all was going fine until towards
the end when the progress bar just stuck in the same position. I left it
over night and it was still stuck. I then tried to cancel the installation
and it won't roll back. I also cannot remove using add remove programs.

Can someone tell me what to do to clear this so i can get it installed.

All the programs are showing in the start menu and all programs run fine so
I don't know what the problem is.

I would very much appreciate some help with this as it is stopping me
installing project and visio.