Every now and again my drive gets to the point it is full and I have become pretty adept at removing unnecessary stuff but always tread carefully! I use CCleaner, Wise Care & Windows Disc Cleanup. I've also recently cleared out old NVidia setups etc which saved a lot of space. Just downloaded WinDirStat to try to see what else might be clogging up the sustem and found a Windows CBS log file takes up 360Mb, Windows Installer Files takes up 2Gb and Nvdia Backend in the App data folder in my users area takes up 1.3Gb. I know I should get a bigger disk and will eventually but it would be good to keep using this one a while longer.
I'm considering updating to Win 10 but needing 3Gb of spare space is an issue and I am also a bit worried that some of my music production software may not work with it. Will have to decide soon!