I quickly link a short description and a link to detailed docu:
I assume you not need to clean, you can remove it ( if unsure move the file to e.g. desktop 
) :
go to C:\windows\system32\drivers\etc and remove the “hosts” file… reboot pc then.
This is a big trouble maker and may your issue is with this fixed.
Example topic: Application hangs when loading a flight "Fly" - #52 by MichaMMA
thats the worst thing with that mod ;)… if you not use the un-installer, the changes in hosts file are persistent.