I had faced same problem "operating system not found" after creating image for the first time with Norton ghost 2003. I had selected my c drive for creating image and it would be saved on d drive. After clicking on few next buttons, it asked me to restart. And then XP never loaded !!
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I had re-installed the WinXp OS SP2
Tip: Always copy important files/folder to some other drive before creating image!
Pritam