Structure of a partition chain
For greater detail on disk partitioning see the subordinate links in the menu for this page, for a simple view see the following structure.
Structure
Legend
+: start/end
-: content
|: alignment
Primary extended partition
+-----------------------------------------------------------------+
| |
Secondary extended partition data |
+-+ |
| |
|Data partition (logical) |
|+---------+ |
| |
|Secondary extended partition |
|+---------------------+ |
|| | |
|Extended partition data |
|+-+ | |
| | |
|Data Partition (logical) |
|+------------------+ |
| |
|Secondary extended partition |
|+----------------------------+
|| |
|Extended partition data |
|+-+ |
| |
|Data Partition (logical) |
|+-------------------------+
Primary extended partition - What contains a Partition Chain.
Secondary extended partition data - The bit of space used to detail the partitioning and is subsequently not part of the surrounding data partitions. On a MS system a full track is set aside for this even though only 1 sector is required. This is due to MS using the CHS to address the disk, Linux and others can be set to not waste the space, though admittedly not much is being lost.
Data partition (logical) - What is typically referred to as a logical partition or drive.
Microsoft NTs
NT4, W2K & XP all I understand store details about the configuration of your bootable partitions in a file named boot.ini which can to be found in the root of the C drive. This file is used by NT loader (boot manager) to provide the chance to choose which OS to start. So if you change the partition table the details in boot.ini may no longer be correct.
Acting now before problem arises
One way to ensure you can always start your NT system, is to make every possible partition bootable in the boot.ini. I am unsure what the maximum number of allowed partitions is, is it 26 (where maximum is limited to the alphabet), 15/16 or 63/64 (due to a table size), but simply put it should be somewhere around these values. Making a number of partitions bootable will provide you with the option of booting the contents of those partitions including ones that don't even exist or don't contain bootable code. Since most people don't have any more than 5 partitions, you can limit the number of entries you create in the boot.ini to say 5 or 10 partitions. Note: I haven't actually done this myself so for the moment at least you'll need to venture somewhere else to find the exact details. This is the sort of thing to do straight after you have installed your NT system or atleast before venturing down the road of repartitioning and configuring a dual/multi boot system.
Roll back
Attempt to return the partition table to its prior state, when every thing was working just fine.
Adjusting boot.ini after the event
If boot.ini is on a FAT file system use just about any system to boot and change the boot.ini, remember though prior to win95, FAT32 is not supported in a standard environment.
Both of the following ways of modifying boot.ini on NTFS can't be relied upon and I have not tried either method.
Use a NT boot CD/Disk and get to a command line where you can then edit the boot.ini.
Don't quote me on this but I think NTFS support is infact built into the Linux 2.6 kernel and it's not just able to read NTFS but write aswell, so it is possible to correct the boot.ini from within Linux.