Lets see if i understood:
4 NTFS partitions.
The boot partition what you mean is the Primary partition right? What is alocated the boot section.
Now you trying to say your friend tried to create an extended partition or extend an already existent partition?
And the last thing, he can't extend an already existent partition with a win98 disk, just with other program, like Fips or MagicPartition.
If is just a boot problem, try to use the windows xp boot disk(The original CD, come with boot in it.) and try to restore the last estable configuration, or try to make repairs reinstalling the sytem.
Maybe your friend subscrible the MBR(Master Boot Record) and now he is having problems to iniciate the operational system, maybe he got a message like: No operational system, or Replace the disk an press ok, or something like this.
If you reinstall the windows xp, the system automatically will subscribe again the MBR and all will come back to normal, well this is what is expected, cause if is more than one partitions the others can't be affected by the problem just only the C:, the others just can't be inicialized.
