Windows 7: Partitions needed for Win7

Hello,
I'm trying to create a new primary partition on Dell inspiron 1370.
The laptop comes with:
a partition with Windows 7 about 60GB
a partition for data about 170GB
a hidden recovery partition for Windows 7 (10GB).
a mysterious partition of about 1MB
a mysterious partition of about 100MB
More details in the picture "ScreenGparted".
I've also attached a screenshot taken with the Disk management utility (ScreenDisk_management).
First of all, have you any idea about the two "mysterious" partitions?
The problem is that I've already four primary partitions and I can't create more.
If I want to create another one how can I do?
I was wondering which among the previous partitions can be deleted.
Thank you in advance for any help

Yes. 10GB Mysterious partition #1 likely contains the recovery image for the system that you can run from the BIOS menu - been seeing this since Dell updated their BIOSes back in 2008 or so. 100MB Mysterious partition #2 is the Windows BDE partition, BDE = Bitlocker Drive Encryption. This partition is used to store some boot data for the system, and also to be there to store temporary data if you ever enable bitlocker on that drive (otherwise it'd have to repartition it on the fly while conversion to bitlocker was occurring, and that takes FOREVER comparatively-speaking.

As to the partition question, you can only have 4 primary partitions on an MBR disk - that's why logical partitions exist, and unless you're going to convert that disk to a GPT-based disk, you'll be limited to 4 primary partition containers.

Thank you cluberti.
Have you any idea about the mysterious partition of about 1MB?
Is it the loader?
Just another question the "unallocated space" shown in Gparted is a logical partition, isn't it ?

Your disk management picture is somewhat odd. None of the partitions is marked as active or primary and the C and D partitions have the "green line" which normally marks a dynamic partition. A more "normal" disk management would look like this:

You have D if you want to install another OS in Dual Boot.

You can make any subsequent data partitions Logical using 3rd party manager like free Partition Wizard bootable CD which is the preferred tool for Windows 7.

I would do the shrink with Disk Mgmt however as it is failsafe.

Make your Recovery disk set as the Recov partition can become inoperable with repartitioning or new OS install. Then you have the option to recover it's space into another partition or create a new one there. If you don't want the factory utilties then you can also delete the other utility partitions.

It appears your System MBR is on C as it should be, however during repartitioning if you lose the ability to boot Windows 7, you'll need to correctly mark it Active, then repair the MBR by running Startup Repair up to 3 separate times from booted Windows 7 DVD/CD.

All of this is covered in Option One of this great new tutorial: Partition Wizard : Use the Bootable CD

You can split one of your Primaries into Logical partitions. This is an excellent read.

Double-post again. Something odd with this Chrome install...

I honestly do not know, as Windows' diskmgmt doesn't see it. It could be a remnant of an OEM load of Windows on that machine (Windows needs at least 30MB or so for boot data, so I doubt it was created by Windows). The unallocated space is likely just that - unallocated.