Microsoft just announced that you should update your windows
as there is a lot of bugs that might be critical for your safety.
The first one is cumulative update for Internet Explorer 7.0 (KB33566), the second in row is cumulative update for Outlook express under Windows XP (KB939123).
Then the Redmond giant follows with security update for XP (KB935839), security update for XP (KB935840) and finally a tool for removal of malicious software dated Jun 2007 (KB890830).
We can advise you to run your windows update and probably feel safer once you do it.