I've reformatted my laptops harddrive and everytime i restart the computer comes up with this error

Invalid system disk
Replace the disk, and then press any key

it says that when there's no disk in the floppy drive, and ive tried many boot disks with different OS version, i cant get to the BIOS setup, it doesnt let me during boot up.
any suggestions?

It's a Toshiba Satalite pro 420CDT (fairly old)
BIOS is the toshiba bios v2.00
Before I reformatted the drive it had Win 95, first edition I think.

if any other specs are needed just ask
I'm stuck at this point and don't know what to do about it, i just need to get to MS-DOS or something close to it. Thanks-

Okay, i've been able to get into the BIOS setup, but it proved useless. No matter what, the computer will have to boot from the floppy, and the error comes up. The BIOS version is 5.40
Please help...