Defrag your Hard disk:

If you are looking for something in a messy room, naturally, it’s going to take you longer to find something. This is a good Example and suits HDD too. Over time, filing system gets disorganized. Periodically, you need to reorganize this filing system on your hard drive. Luckily, Windows has a good utility called Defrag that will put your system in order.

1. Open the Start Menu
2. Click on My Computer
3. Right Click your C: drive.
4. Scroll down to the Click Properties
5. In the Properties Menus, Open the “Tools” menu.Choose Defragment.
6. In the Disk Deframenter menu. Click on Defragment

Now wait for some time untill it finishes this task and Organize your HDD. Reboot your Computer afterwards. Registries can also affect somewhat for slow booting time, 

so better Download Registry Cleaner tools