I have 280GB avaliable for usage at the moment, but i have 600GB in total. How do exactly can i allow my self access to the full 600GB. I have less that 1GB left and i need to use approx. 3GB up but cannot.
Welcome
You can reduce the space that is used for restore points. Dont eliminate the space, you will need restore one day. http://www.vistax64.com/tutorials/76227-system-restore-disk-space.html
If after the change you still would like additional space, download windirstat to see where the usage is.
Windirstat will show how the current space is being used and how we can expand it.