Okay ...first off, please download the following freeware (don't buy anything) security program, Malwarebytes' Anti-Malware
A download window should come up automatically
...run and install the same, then carry out a full system scan using the program, and remove the security threats detected, if any.
Done that, there's a handy freeware utility I would suggest you to download, as follows: http://www.ccleaner.com/download
Done that, run the same and click on the 'Run Cleaner' button in the window that comes up in order to do a comprehensive cleanup of useless data in your system.
Next, click on the 'Registry' tab present in the left pane, then scan for and fix issues found in your registry.
Now, click on the 'Tools' tab present in the left pane, then under the 'Uninstall' tab, look for and highlight programs present which you don't need ..and click on the 'Run Uninstaller' button to uninstall the same.
Under the 'Startup' tab, look for and delete the program entries scheduled to run when you start up your computer, which you don't use, or need to run at startup.
Let me know if all of these makes any noticeable change in the functioning of your system.