Is your system slow or are you making it slow??
How to know if your PC is improving performance with these tips?? just take a look at your idle RAM and CPU usage before and after on the task manager
See how much RAM my pc needs just to run?? the lower this value the less you will need to force your components to the max! and less LAG!!!
If you're still not quite happy about the results you should disable some services
Then a good start will be to check the automatic starting services and disable the ones you don't need you can put them in manual start so that when a program needs that service it can run it first