If you install two operating system like windows and linux or you reinstall windows (98,2000,xp)operating system in that case you see option for choosing operating system but you want only one operating system at starting time. Then follows these steps and remove other option.

Right click on “My Computer” icon and choose “Properties” and goes to “advance” tab and click on ” Settings ” under Startup and Recoveryoption, after this click on edit option now open a boot file in this file you see two or three lines like this “multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=”Microsoft Windows XP Professional” /noexecute=optin /fastdetect”. In these like 1st line represent 1st option, 2nd line represent 2nd option and respectively. Now you can delete any line which you dont like but before doing this copied this file. Now restart your system and you can see your problem removed.