Just a tip: it's not a good idea to pull the plug when your PC is running. It's a good way to fragment your hard drive.
Start by downloading ccleaner. Use the registry tool to scan and repair the errors. You may need to run this several times to fix everything. Then use the file and application tools to clean up some of the clutter.http://www.piriform.com/ccleaner
Boot into safe mode with networking. Download, install, and update malwarebytes. Do a full system scan.