There are three steps here:
Step 1: DIAGNOSIS :
Check if the sluggishness of your comp. is really due to the same problem I had faced :
Right Click on Task Bar > Open Task Manager > Click on Performance Tab . You should be looking at the following screen
Ideally, the CPU usage (circled in red) must be a value < 65% for smooth performance. But values upto 80% are tolerable.
BUT,if this value exceeds 80-85%, your computer's slow behavior is definitely being affected by this factor. And you need to fix it.
Step 2 : THE FIX
In Task Manager, open the Processes tab, to the left of Performance. Sort the processes by memory usage.
Look at the Description column and close all the processes that you think are unnecessary and that are by 3rd party companies that you don't normally use on a day-to-day-basis. These might be running in the background without your knowledge and might have started running when you booted up your computer.
Now check back in your Performance tab. The CPU usage should have reduced.
Step 3 : CHROME, THE SILENT KILLER (OPTIONAL STEP)
If you're running Google Chrome, this might be another tip you could look into.
b) This is what the Chrome Background Pages Task Manager will look like.
In the event that your comp. is exceptionally slow with Chrome running, feel free to close any and all Extensions that are running in the background. It will Not hinder your browsing in any significant way :)
Once you end said extensions,close any pop-ups that ...well..pop up :D
Do not close the Plug- ins. (Flash etc).
These steps should relatively get your computer running a lot more smoothly :) :)
Feel free to comment on any other observations or problems you make or face.. Hope this helped!