Hi,
Thank you for the reply.
PBR Image drive and WINRETOOLS drive are the recovery partitions and contain the recovery image (PBR Image) and Windows Recovery Environment tools (WINRETOOLS). The reason why it is showing in red is that this drive had got very little free space.They are important for recovering the system in case of a software issue and should not be deleted.
The PBR and WINRETOOLS drives are provided by Dell. I would suggest you to create a recovery drive. Follow the steps given in the link below.
Create a USB recovery drive
http://windows.microsoft.com/en-us/windows-8/create-usb-recovery-drive
Feel free to write to us if you face any further issues related to Windows.