Unwanted Scheduled Tasks
By default windows 7 has several tasks enabled that run whenever they want to on your system which can cause stutters and unwanted hard drive reads and writes. Ever been playing a game and all kinds of lag starts happening for no reason? One of these is probably why.
Open the Control Panel
On the left hand side tree locate and open the following trees.
+Task Scheduler Library
Now in each folder select the folder
Then select the task in the middle column
Then on the right column select Disable for each of these OR Download A Registry File for windows 7 64bit to do it for you.