You must edit your boot.ini (first make backup).
my boot.ini looks like that:
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect
I thing that you have two rows started: multi(0)disk(0)... its the same like in boot option when win starts.
So delete the second row which represent non working option in boot option menu.
Also check row started: default=multi(0)...
It must be same like row: multi(0)disk(0)...
then save boot.ini and restart.
Boot.ini have hidden file attribute, so you must have switched on Show Hidden files option in windows.
Pay attention if you make something wrong win. dont be able to start. You will be only able to repair it in DOS mode from your backup.