MUP.sys in XP?

When I boot in safe mode, and can see the system files being loaded, and my system stays at the file MUP.sys for ages!! Anyone know what it is, and how I can fix it?

I did a repair and it fixed it. start like you are gping to install then after it confirms that you want to use the same partition that winxp is already on it should give you the chance to run repair. It looks like an install but it keeps your settings.