Why is my computer running so slow? If you think about this question often, and are looking for a way to speed it up, you will be happy to know that you can do quite a few things to fix the problem. 

Start by checking your hard disk: Open "My Computer," on your desktop and then right click your hard disk and click "Properties." You can tell if your disk is really starting to fill up. This is one of the most common causes of a slow computer.

Click on "Disk Cleanup." When you do this, you can help delete the temporary files and a number of other unused programs or files that you are not using. These fill up your hard disk and take up unnecessary space on your hard drive.

Choose the "Tools" tab and run a disk error check. If it finds errors and fixes them, that saves space.

On the same tab, run the Defragmenter (only after an error check, for safety's sake). Think of your computer as a filing cabinet. If you've put some files in the drawer sideways, and some papers have spilled loose into the bottom, and a few of the folder labels have peeled off, it will take you much longer to find the document you're looking for. Defragging essentially organizes those file folders, puts them together and leaves empty space in the back of the drawer for more by moving program data around on the disk. Just as you can retrieve something from a neat, organized file cabinet more quickly, your computer can find what it needs more quickly, too. 

Empty your Recycle Bin whenever it is getting full to help clear up space.

Download
registry repair software. The computer's registry is like its brain--when it gets too full or full of incorrect information (errors), the computer can't run as quickly. 

Last but not least: You are not using the tool I recommend on my personal blog and you keep telling tell yourself "How to speed up my computer". You can also check out this post on my blog: Why is My Pc Running So Slow?