This occurs if you have too many Applications installed, or the Hardware Components are not sufficient to perform faster.
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Try these steps- Hope this Helps
1) Try the Performance troubleshooter
The first thing that you can try is the Performance troubleshooter, which can automatically find and fix problems. The Performance troubleshooter checks issues that might slow down your computer's performance, such as how many users are currently logged on to the computer and whether multiple programs are running at the same time.
Open the Performance troubleshooter by clicking the Start button , and then clicking Control Panel. In the search box, type troubleshooter, and then click Troubleshooting. Under System and Security, click Check for performance issues.
2. Delete programs you never use
3. Limit how many programs run at startup
4. Defragment your hard disk
5. Clean up your hard disk ( Run the Disk Clean up under All Programs - Accessories - System tools )
6. Turn off visual effects
a. Open Performance Information and Tools by clicking the Start button , and then clicking Control Panel. In the search box, type Performance Information and Tools, and then, in the list of results, click Performance Information and Tools.
b. Click Adjust visual effects. If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
c. Click the Visual Effects tab, click Adjust for best performance, and then click OK. (For a less drastic option, select Let Windows choose what's best for my computer.)
7. Check for viruses and spyware