I am running a tripple boot system.

Pri. Hdd 1st partition Win 98. fat 32 hda1
Pri. Hdd 2nd partition empty fat 32. hda ?

Slave. Hdd 1st partition Xp. fat 32 hdb1
Slave. Hdd 2nd partition Knoppix. hdb2

I would like to know if there is some way that i will be able to boot my
Xp partition if i re format my Pri Hdd. giving me more space as i dont want
98 on there.
Im very happy with knoppix, thats easier for me to reload.

All boot info is on the Win 98 partition. Tried changing xp drive to master
but wont boot as boot partition is on 98.

I dont want to have to reload everything to do with Xp as thers a lot on ther if poss.

Hope ive given enough info as im new to this

Any help

I don't know all the bootloaders which can be used with PC. But if you use GRUB there is no need to do anything. You can just format W98 partition without any additional effects.

The first stage of booting process is done by BIOS which read the Master Boot Sector (MBR). MBR is located always on first sector of booting HDD (in case of new BIOSes it doesn't need to be master drive) and doesn't belong to any partition.
HDDs swap which you did probably resulted that BIOS tried to read empty MBR.
So to boot from the second (currently slave) drive firstly you need to get correct MBR on this drive. It can be done using the tools proper to the bootloader which you have used.