My favorite free tool is called Win Fixer, which works perfectly on Windows 2021, XP and Vista. This tool can detect all kinds of errors including Windows updates, internet explorer, runtime problems, driver issues, missing DLL files, invalid application paths and more. And because it's free, I don't have to pay anything to keep it updated. You can download all kinds of tools from the net, but most of them don't work as well as Norton Security Scans.
It detects and removes malicious programs such as: Trojans, backdoor programs, adware, spyware, viruses and other threats that may damage your system or steal personal information. When performing scans, it removes malware, spyware, adware and other threats while leaving all the important files and settings untouched. This result makes your computer free from all viruses, malware, Trojans, worms and other threats - which means that your computer will run more efficiently and prevent any future infections from occurring.