If your system has been bloated with malware, viruses and addons you never wanted, but which steal valuable resources from your system, I can backup your data and run all your files through antivirus systems that run outside of the operating system and as a measure of last resort, reinstall your operating system, if you still have the original installation medium.
If you happen not to have the original operating system on a proper installation medium, or if you're not satisfied with what your computer uses now, my recommendation for your consideration is to go with a Free/Libre and Open Source Operating system. I recommend installing GNU/Linux.
GNU/Linux offers features other Operating systems do not have. It is different in both looks and behavior but like other operating systems you won't be labeled a pirate if you copy it and/or give it to a friend. There are usually more than one alternatives ot expensive software you rarely have need for.