1. PC will look for op system on a floppy disk if found will boot from that. If not found will then :-
2. Look for op system on a CD in the CD drive. IF a CD in drive has an op system (your reload CD) then you may get the prompt "Press any key to boot from CD".
If no CD in drive or no op system on CD then PC moves onto :-
3. Look for op system on primary active partion of Hard Disk Drive (HDD)plugged into IDE 0. This is normally the C drive where your windows system is located.
This is a good set up in BIOS as it allows you to boot from a floppy or CD and effect repairs if the windows system fails.
Just make sure when you reboot that trhere is no floppy in the drive and no CD (your reload CD) in the CD drive.