When I close my FxDK it wont re-open I have no Idea why this is happening 
Check if background processes are running, or simply find the actual shortcut in your AppData/Local/… and start it that way.
Sometimes the FiveM processes keep lingering, killing them in task manager will allow you to boot up FxDK or FiveM again.
cant find any process relating to FiveM unless its unknown or unidentifiable to fivem.
can someone please help me still? Thanks!