MSI K7N2 Delta Problem HELP

[hogboy]

I have built a new pc with the following specs
AMD 3000xp cpu
MSI K7NT mobo
2 x geil 3200 512mb ram
Maxtor 120gb 8mb buffer
ATI Radeon 9800 pro
Pioneer dvd writer
Creative Live value soundcard
AMD 3000xp cpu
Windows XP Pro with service pack 1
When i set the fsb to anything other than 100, just after the boot screen
i get the helpful message 'ntldr missing, press alt cntrl delete to restart'
I have reinstalled windows from scratch, and tried repair, but nothing seems to help.
I have used live update to get the mobo up to date.
Can anyone give any advice at all?????????????????????????????????????????
Any tips appreciated.
Thanks in advance

[Lexus]

Possible:

Check that your jumpers are set correctly to master on both drives and the connectors are firmly in place on the primary and secondary channels

Lexus

[RoGuE|SaBeR]

Whats the PSU?

[hogboy]

Its an antec 450w, and i have plenty of cooling on the cpu, case and radeon.
I dont understand why changing the fsb would cause this error?