Quote Originally Posted by Spikeanoid View Post
Delete unused (large) files, uninstall unused programs, defrag your hard drive assuming you don't have a solid state drive. Disable unused programs from running when your PC boots. Like was mentioned, install and run malwarebytes regardless of what AVG finds.

What are your system specs and operating system? If nothing seems to help and buying a new laptop is out of the question, swapping your traditional hard drive for a solid state drive is by far the best thing you can do to speed things up.
Going on what he said, you are also going to want to clear out any caches/temporary files. You can use CCleaner (Free Program) to safely and quickly clean out the temporary files and cache.