I've seen defective floppy drives keep hard disk drives from booting, but can't attest to one making a computer reboot though it it entirely possible.
Process of elimination would dictate that you try another floppy drive to see if the problem persists. If it does, then the problem isn't a defective floppy drive. I would then try reseating my System RAM (memory chips). If you try this, make sure the computer is off and the power cord is unplugged (because power is still on to the motherboard on current model computers even if they are turned off) and be sure not to touch the connectors on the memory chips themselves as this could damage them.
If you are uncomfortable going inside your computer, you could buy or borrow an external USB floppy drive to connect to your computer.