Here are very simple security tips for your Windows personal computers.
1. Create a standard or limited windows user and use this user from this point on.
2. Install Microsoft Security Essentials. You will be prompted the admin password. Turn on the firewall and run a scan.
3. Use non-native browser for your OS. You can either go with Firefox or Google Chrome.
4. For your choice of non-native OS browser, think about installing some smart Ad blockers that are fair to good advertisers and properly block intrusive advertisers.
5. Buy a packet USB drive and do a cold backup of your files to USB once a month and keep a copy of this in a house and another copy outside your house (family house or friends house or even at work).
6. Pick a secure password manager solution and use it. Never allow browser to save the passwords locally because that is not as secure as dedicated password management solutions such as: 1Password, LastPass, KeePass and others.