FI system partition on my data after installing new computer

[cynicoren]

Hi,

I added my old HDD to my new computer. It is one physical drive divided into 2 partitions,
but in the Disk Management I see "EFI system partition" on one partition that have all my music and family pictures, and the other partition is OK (in the picture I'm posting it's Disk 2 with the drive I and the EFI partition).
How do I make it a regular partition again?

EFI system partition on my data! - Album on Imgur

Thank you

[yabay]

-Start the command (start>find>cmd)
-Type DISKPART directly
-In the diskpart:
> Type: "List disk" press enter
>Find your drive (shown as disk 0, disk 1, disk 2 etc)
>Type: "select disk 1" press enter (you must type your own disk number)
>Type: "clean" press enter

Attention: You will loose all data and partitions on your disk. Before proceed, back up your data.