If you have to run Windows XP beyond the end of support deadline, security firm F-Secure has published some helpful information to help users do that safely. At the very least you should:
- Install all updates up to and including the final update.
- Move off Internet Explorer as your default browser. Install Google Chrome or Firefox.
- If you are running Microsoft Office, fully patch that and tighten up security. Be wary of documents from unknown sources.
- Remove any software not in use, including both third-party software and stuff bundled with Windows XP.
- Uninstall Java unless you absolutely need it.
- Install an up-to-date security product that includes antivirus and firewall.
- If possible, disconnect the system from the internet. If not, firewall it.
- Don’t get complacent about security.
- Come up with a plan to transition from Windows XP to a newer operating system. Microsoft has some resources to help