lost access to my partitions

[christaras]

Hello. Plop boot manager was working fine for about a week. I had installed plpbt.img on diskette.
I had deleted and reinstall many times.

Yesterday when I pressed 4 to delete and then 9 to reboot, plop could not locate my hard disk partitions! I took out the diskette and when I reboot I got the message about no operating system found... and fdisk was telling me there are no existing partitions...

Had to repartition, reformat, reinstall win98, win xp and all the programs...

Can you tell me what happened and what can I do next something something like this happens?
Win98 is the system partition containing the boot files. Can I write them on diskette and boot next time it happens? Are they hidden? I can only see boot.bak, dont see any ntldr file.