A few suggestions:
1. Start with the obvious: Look in your list of installed programs to see if you can identify and remove anything that's unwanted.
2. Run a FULL scan with your anti-virus program.
3. Download, install and run the free version of Malwarebytes Anti-Malware:
http://www.malwarebytes.org/products/malwarebytes_free/
(When installing, ensure that you remove the tick against the option to install a trial version of the 'PRO' program).
4. Go to Start > Run and type msconfig. Go to the Startup tab and disable anything you don't need.
5. Go to Start > Run and type services.msc. Look for any services labelled as 'automatic'. If you're confident that you can do without them, either disable them or, at least, change them to 'manual'. (Double-click on an entry to modify it).
6. Download, install and run CCleaner, paying particular attention to any programs that are set to run automatically (which might have escaped steps 4 or 5):
http://www.piriform.com/ccleaner
7. If you know the
name of a program (which isn't evident from your link), Google that name together with 'remove' to seek instructions for getting rid of it.