windows 95 wont start

On older systems the FDD Controller was a expansion board installed on the motherboard,so the controller card could be gone

Check the BIOS settings in Setup and see if it is being detected

Using a startup disk,try booting into safe mode open Device Manager,the check for any exclamation marks,if so use the operating system disk to reinstall the drivers

with both drives giving an error this most likely is a hardware problem pointing to the controller card.

A little more info will help.

What is attached to drive "D:\" A hard drive, CDROM or tape drive?

If there's a tape backup drive in the system that the floppy drive attaches to that may be causing the problem. The tape drive may be connected tothe mother board or to a controller card.

If so disconnect the tape drive and or remove the controller card if installed. Connect the floppy directly to the mother board using the cable already attached to the floppy. If the card was installed you need to turn on the floppy controller in the system BIOS.

After doing this if the computer completes bootup then the tape drive or controller card was causing the problem.