Hello Rammi,
in the other post you complain that port security works and here you complain that it is not working
it is the same switch, what IOS version is running?
can the original PC or vista PC (not clear) be running any virtualization software? they can associate additional MAC addresses to the PC NIC.
also, using port security max first MAC address seen on port is considered secure.
I would suggest you to start to teast by adding manually the MAC address.
Besides this, the secure host MAC address table has its own timers and can be influenced by some additional commands the aging time can be based on inactivity on the port or it can be absolute.
see
http://www.cisco.com/en/US/docs/switches/lan/catalyst2950/software/release/12.1_22_ea11x/configuration/guide/swtrafc.html#wp1038501
Hope to help
Giuseppe