Windows has some built in tools you can use and they are found by (Win7) clicking on the Start Orb - Control Panel - System and Security - Find and fix problems.
Under System and Security click on Run maintenance tasks - Advanced - Run as administrator - Advanced for Auto repair and then do the same Check for performance issues.
Also go Start Orb - type disk cleanup - right click on Disk Cleanup and select Run as administrator then follow the prompts - this could free up a few GBs of HDD space which will aid Virtual Memory (VM).
StartUpLite is a program that can identify and remove unnecessary start up programs that will be unnecessarily taking up memory and affecting performance.
https://www.malwarebytes.org/startuplite/Adware and infection can also have an effect on performance so download/run AdwCleaner
http://www.bleepingcomputer.com/download/adwcleaner/Click on Scan and it may list programs in the lower window that you can deselect if you want to keep them when it has completed its scan.
Click on Report and it will show you if it has found anything to remove - close the report then click on Clean.
It will produce another report on what it has removed after the reboot which you can then close.
Also run a scan with the free version of MBAM
https://www.malwarebytes.org/It will auto update its Definitions on installation and it will prompt you if needed, to update those when you run the program at a later date.
Next is to perform a Defrag - click on Start Orb and type defrag then click on Disk Defragmenter.
Click on Analyze and when that's complete it will display how much the disk is fragmented in % - click on Defragment disk and wait for it to complete which can take some time depending on the amount of fragmentation.
It does have a default defrag but that is normally set for something like 3.00am on a weekly basis, but if the computer hasn't been left switched on then it won't happen.
Let us know if any of these steps have improved the performance.
