To create a second primary disk, you'll need to use a partitioning tool to hide the first primary disk. After the second installation, you can then unhide the first one.
Rather than play this game of hiding and unhiding partitions, it's best to use a boot manager
to take care of the whole thing. Some such products are :
BootIt NG ($34.95)
Support of over 200 primary partitions (if desired). I've used it and it's probably the best.
GAG (initials, in spanish, of Graphical Boot Manager) (open-source)
Allows boot of up to 9 different operating systems installed in primary and extended partitions. Never used it.
Partition Commander 11 ($49.95)
No info on maximum partitions number. I've used it a long time ago and it worked then pretty well.
Norton PartitionMagic 8.0 ($69.95)
Otherwise called BootMagic, no info on maximum partitions number, and seems to only support partitions up to 300GB. Never used it, and I usually stay away from Norton products.
Warning: Before playing with partitions, take great care with your backups.
The NT systems can have 4 primary partitions without any problem + extended.
I have never seen any problem with it, or any real reason for doing it.
If there is also a hidden partition, then you would see it in Easus. Notes: There are some tiny portions of unallocated that might not be visually represented in Easus and in disk manager
Mentally I picture many primaries like this.
|---primary---|------Primary-----|------Primary-------||==extended==with logical==||
Being old school and trying to keep the thing as normal and regular as possible i prefer only 1 primary.
What I concider the "normal method" is like this.
|---Primary----|----------The space called extended where Logical Drives are set-------|
Which to us after that is all created looks like this.
|---Primary----||=====Logical============Logical============Logical===all in that ext space=||
|---Primary----||=====Logical=====|=======Logical=====|=======Logical===================||
See the differance? Well dont feel bad because I don't totally understand either.
Right now you can not make a logical without that Extended hole space made First.
Logicals are all created IN the extended space. A primary does not use the extended space method. Until you or the progam remove or move any primaries that are in the way, and create or enlarge an extended space, you will not be able to put Logicals INTO the extended space.
Without a backup, and knowing that primaries ARE a workable method, the least would be a clone backup of the whole drive before proceeding. Most methods for partition conversion, require entire re-write of the data, and messing with the partition table. they wouldnt let ME do that without a backup :-) so why trust software .
Best Answer
See "Method Two" from this guide:
http://www.sevenforums.com/tutorials/146694-partition-extended-logical-drives.html
added by barlop
Looking at that webpage, that webpage lists two things, creating a partition with diskpart which it calls "method 1". But what you want, is under "Method 2" on that webpage, it mentions how to convert primary to logical. It says to use Partition Wizard which can be bootable CD here or bootable USB here. I haven't tried it but I see from that webpage It lists partitions, it doesn't list "convert" under operations, but it can convert- you can right click the partition choose "modify" then "set partition as logical" and that does it. It can also "set partition as primary". And it mentions that you can run diskmgmt.msc as administrative, and right click a partition and choose "shrink volume" or "extend volume" (no doubt non-destructively and no doubt it does likewise with the partition and not just the volume within the partition.).
There is also a note on that page which i'll describe here, you need an active primary partition to boot from. On a windows 7 system the active primary partition is called "system reserved" and is 100MB/200MB (as opposed to the C partition). On XP there is no "system reserved partition" and the active partition is typically C.