Delete Unnecessary Data

There are tons of pictures, files and data in our documents folder which we keep accumulating but we never use, I recommend that you remove any unneeded files as they burden the disk which may make it slow. Any free space is a breather for the disk, so don’t overload it with heavy files and data which you don’t need.

http://www.jam-software.com/treesize_free/

Uninstall Softwares

This is one of the most important part, most computers become slow not because they have aged, but because they have too much to handle. Identify the softwares which you use and need- keep only these softwares and uninstall rest of them which are just adding burden to your PC. This is  a slow and time consuming task, but it does give you noticeable improvements.

http://www.revouninstaller.com/

Optimize Startup

Startup tasks are those which are started automatically at starting if Windows. More often then not, they are the primary reason to make PC slow, to make your PC respond faster and boot quickly, follow the instruction here to remove some load from startup list.

http://technet.microsoft.com/en-us/sysinternals/bb963902.aspx

Run Registry Cleaner

There are many free registry cleaners available which remove the old and corrupt entries which tend to accumulate and make PC slow. You can use some free tool like CC Cleaner to clean up the registry.

Run Virus Scan

If you have an antivirus installed, run a full system scan. If not, install any free or paid anti-virus of your choice and run a full virus scan. Sometimes viruses also make your PC slow. They are also a threat to yourdata and information security.

Run Disk Cleanup And Defrag

Disk cleaner and disk defragmenting tools are in-built in Windows, It is recommended that you run it every couple of months to clean up the disk and make it faster.

Create New User Account

This part is optional, but creating a new user account will give a fresh look, a clean desktop and feeling of using a new-like PC for most users. It does not increase the speed much, but it does create a cleaner space to work.