Problem on XP reinstall

Further to my questions a few days ago, I have completed the reinstallation of XP but have one silly problem that is probably of my making. When the computer boots, I get a message asking which operating system I want to use, XP or "unidentified operating system on Drive C ".

I had a lot of messing about during the installation period, and used Partition Magic and also an old Win98 boot disc. I suspect this unidentified operating system is left over from one of these. I have looked at drive C but can find no trace of a dos file which was my first thought. It does not stop me using the computer, but is irritating! Does anyone please have any suggestions as to how it might be stopped?
Richard

 

Run msconfig click on boot.ini and then check all boot paths. edit as necessary.