[im_not_1337]

I would highly highly recommend putting a password on your computers. The easiest way to accomplish this is putting it to auto lock when your screen saver activates, then have your screen saver lock like every 20 mins or so. Then whenever anyone is away from the computer for 20 mins or longer, it will auto-lock.

Also, as far as scanning for malware. Use kaspersky's online antivirus scan. They have the highest detection rates and will detect almost everything. Also, you might want to look through your windows folder and windows system and system32 folders. These are the most common locations for bad malware such as trojans, keyloggers, and backdoors. If you see anything suspicious, upload it to virustotal.com. Also, i suspect the maids were likely just browsing the internet. You may want to check Ie/firefox's history/temp and see.

Good luck. If you have any other questions, lemme know.