Assuming you are using Windows XP or greater version, it is important to make the habit to check every computer that is under your care. The following is a checklist for you to follow. You should also be aware that routine maintenance tends to evolve over time based on an organization’s past problems that might need special attention, if so, you can always start with this list and then add to it as need arises:
1. Change the administrator password and/or use a strong password (at least 8 characters combination).
2. Check that Windows Automatic Updates is turned on and working. For applications that users routinely rely on, you might also download and install any critical updates
3. Check that Anti-Virus Software is installed and updated. I recommend on previous articles to use just a strong Internet Security Suite.
4. If you work for an organization of a company, were sure the case has not been tampered with, is the lock secure?.
5. Check Windows Event Viewer. Take a look at the security list, looking for failed attempt to access the system going to Control Panel, Administrative Tools, Event Viewer, Security log.
6. Be sure that there’s data and/or system backup exist. (This is the most important of all, with today’s external hard drives prices being so low, there’s no excuse not to backup your entire system).
7. Double check you are taking advantage of all security futures of NTFS