Why you don't want your Main C: drive to be full on a PC

    When your main drive or the drive that has your Operating System on it (Windows) fills up to 80% you will notice significant reduction in speeds on your PC because your computer needs that extra hard drive space for many reasons but the main one is it uses a portion of it just like the PC uses RAM or random access memory and it's called a Paging file.  This setting is in the Control Panel and then System settings, then advanced system settings.  The top box that says Virtual effects or Performance and then the middle tab is where this setting is and I usually set mine to be a minimum of 3000 mb to Double the amount of ram in your PC so if you have 8 Gb i would set mine to 16000 mb as the maximum then click set (also you must uncheck the box at the top where it says automatically set).  I recommend having a second Hard drive just for installing your programs mainly if you have a drive that's only 120 Gb because windows tends to take up about 40 Gb in the beginning and quickly fills up the rest on drives that small with all the things that make Windows so User friendly and easily installed like plug and play drivers etc.