Running Windows 7 64bit on Samsung 4gb ram 500gb. On 17-7-15 I had 395gb free memory on the 18-7-15 I had 390 GB used. 5gb used although no downloads. I have not downloaded any large items and it now shows that I have 381gb free. Can you suggest as to why I have used 14gb on my C: drive without downloading any large items. (About 10 small ones). I have done numerous disk cleanup, have removed old restore points. moved numerous files to external hard drive and the memory still goes down