Just remember we are in uncharted territory here so it's entirely possible that we may kill the thing and have to start over from scratch. If you have any pictures or other data that you can't afford to lose and haven't backed up now is the time to do that!
I found some screen shots on the Hiren site. It's from a slightly older version but should be close enough.
When you boot to the CD you should see:
You select DOS PROGRAMS. Then you should get:
Tell it: 9 (for Next) and you should get:
Select 1 (for MBR (MASTER BOOT RECORD) Tools. You should get
Select 8 (for More) and you should get the rest of them. Hiren says he has MbrFix 1.3: on the disk. If it doesn't show up on either menu then we will just have to use one of the other tools. MBR Wizzard looks good:
To Save the current MBR:
(IF you have to go back: To restore to the saved MBR:
To look at the partitions:
(This should show the three partitions we saw before. I assume they are numbered in the same order 0, 1, 2 - You should be able to tell by the size)
To unHide a partition use
MBRWiz /Hide=0 /Disk=0 /Part=2
(Make sure /Disk and /Part are correct for the one you want to unhide)
To Have it write an XP MBR
MBRWiz /Repair=1 /Disk=0
To Delete a Partition:
MBRWiz /Part=2 /Del
Make sure you are deleting the right one and not the big one for the C:\ drive!
As mentioned before I would run some of the Anti-virus scans from Hiren before trying to fix the MBR. This beast is really nasty and if we don't get it all it will just reinstall itself.