Hey there, George Mahi.
If you have important data on that drive you should connect it to a different computer and use it as a secondary storage HDD just to backup your valuable files. While connected to a different computer you could try 3rd party software in order to convert the dynamic volumes back to basic without losing data, but not that this is not 100% guaranteed to work.
Your other option is to simply reformat the drive and make a clean installation of Windows, just as you suggested.
Hope that helps. Please let me know if you have any questions.
Boogieman_WD