Passwords don't work


Today I’m experiencing this strange problem. If I log out of Windows (XP) and try to log back, the password is incorrect. Also, some passwords I use on forums have to be previously reset so I can log in …

What’s the matter? Is there any spyware here? I have AVG anti-spyware, Kaspersky, Spybot and Ad-Aware. Currently I’m scanning my computer from top to bottom, but still nothing found.

Any idea?