[Shasown]

Its not memory on your hardrive its running low on its RAM memory thats running low. Close down, and if need be uninstall unnecessary programs you have running in the background. Get a decent program to not only monitor whats running but also clean your registry periodically.

Make sure you use a decent anti malware program as opposed to several cheap ones and scan your whole computer regualrly, and then bin all old processes you have running you dont want or require.