Cannot create a new volume on unallocated space

[Sheimi]

I keep getting this error in particular "You cannot create a new volume in this unallocated space because the disk already contains the maximum number of partitions". I am trying to install Windows 8 as a dual boot on Windows 7. How would I install Windows 8 as dual boot?

Spoiler

Thats how much I have unallocated

 

[KDH]

The message is self-explanatory: you already have four primary partitions, which is the maximum for ms-dos partitions tables. And yes, you are using an ms-dos partition table, since it what windows creates by default all the way up to Windows 7.

You have two options for creating more partitions:

1. Expand your extended partition (the green outline, NOT what is inside it) to fill all of the unallocated space, then create you Windows 8 partition inside it. This is the safer option, but might not actually work; last time I checked Windows REQUIRED it's installation partition to be a primary one.
2. IF AND ONLY IF THIS IS A 64-BIT SYSTEM WITH A 64-BIT OS & UEFI then you can convert the disk to use a GPT partition table, completely removing the partition limit (though Windows will only see the first 128), and create you new partition afterwards. This is potentially dangerous however, as a single mistake will completely destroy all of your data. It involves using a Live Linux distro to erase, then carefully reconstruct your partitions.

I'll provide step by step instructions for either choice if you like, but be absolutely sure your system meets the criteria for two if you want to try it.