Serious question - how do they know my password?

[slush puppie]

Sorry if this a bit long but please hear me out. This is driving me mad. It started when an ex-friend ® used my paypal account to buy xbox gamer points 'by accident' as according to him, my paypal had stayed logged in on his xbox from when we both used it to buy points 6 months before. I wasn't sure whether to believe him so I changed all my passwords - paypal, hotmail, and facebook - to 'antg6134'.

Then I got a text saying from an anonymous number saying 'how much does an ant weigh?'. I honestly just thought it was one of my friends messing around, I replied 'depends on the ant' and they replied 'ha, you're a loser [my full name]'. At this point I looked at the number and realised it ended 6134, which I didn't think could be a coincidence, as I know there are services where you can send texts online and pick a fake number.

I didn't know whether to go to the police, or whether it was just a coincidence, and my friend said they would not take me seriously. So instead I changed all my passwords again and scanned my computer for viruses and spyware, wanting to see if there was a keystroke program installed. Nothing was found. I also set up login notifications for facebook, but they were getting sent to my old university email which I no longer had access to.

Finally I changed the email address they were going to and I saw that my other friend (J, who is best friends with R) had logged onto my facebook on the 19th March, well AFTER I had changed my passwords. How are they still getting access to my passwords?! It is not like they are getting in via a security question or something and then resetting the password, because all my passwords are still the same - they actually KNOW my password, even though I keep changing it.

Please help, I don't know what to do I don't want to confront them yet in case they do something awful.
I already did full anti-virus and spyware scans, which returned nothing. If I do have a keystroke program installed, it is going undetected by the software I am using to find it. Is there a particular software program you would recommend I install?

[Yard Dog]

Run a full scan using your antivirus and malwarebytes and superantispyware . you may have a keylogger program installed w/o your knowledge .