The Department of Homeland Security (DHS) is recommending that Windows Operating Systems users apply Microsoft security patch MS06-040 as quickly as possible. This security patch is designed to protect against a vulnerability that, if exploited, could enable an attacker to remotely take control of an affected system and install programs, view, change, or delete data, and create new accounts with full user rights.
http://www.dhs.gov/dhspublic/display?content=5789(ed- a follow-up statement warning about the dangers of leaving windows open while away from your house is to be published later)