When you start the PC, the first screen should tell you how to get into the BIOS setup routine. Once there, find the section that controls the order in which the BIOS looks for boot devices, make your hard drive number 1, and put the floppy last. Then, whenever you start the system, it'll stop looking for boot devices after it finds the hard drive.
If ever you need to change that back, you can...
There is a setting in Windows 98 and Me to stop Windows, while starting up, to look for a floppy disk, at, if I remember correctly, Control Panel>System--->Performance tab. Is there a similar setting for Windows XP ? There is no such thing at System--->Advance--->settings for Performance. Thanks.