Re-Install Parallels Preparation

My iMac has been having a lot of problems lately and throwing a lot of errors in the various system logs. I am planning on reinstalling everything from scratch and want some advice on how to reinstall parallels. For example, I have been a long term parallels customer and have done many upgrades, so what will I need to do the installation again? I am currently on version 11.

 

Hello ArtW,
You can just download and install Parallels Desktop 11 but during activation, you will be prompted to enter Parallels Desktop 11 key and a previous version key just enter Parallels Desktop 9/10 key and you will be able to use Parallels Desktop. Also, make sure you have taken a backup of the VM before you wipe the Mac.