It is vitally important that your computer receive all of the critical updates sent out by either Microsoft or Apple.
Microsoft is extremely consistent with their updates, sending out updates on the second Tuesday of each month (called Patch Tuesday) as well as any that need immediate attention. Make sure your computer is set up to receive and install them - this is a requirement:
- In Windows 7 (or Vista) click the start button (the Windows button) and choose Control Panel.
- Click the System and Security setting and then Windows Update - "Turn automatic updating on or off" and make sure that "Install updates automatically (recommended)" is chosen.
Apple sends out updates an an as-needed basis.
- Click on the Apple menu in the upper left corner and choose System Preferences
- In the System area, choose Software Update - make sure "Check for updates" and "Download important updates automatically" are both checked.