Ok man i know what the problem is as I also had it.
It is not spyware or a virus it is simply that paticualr screen saver (the windows text screensaver where you can write your own message as a screen saver).
I switched to that screen saver once and as soon as I did it my screen saver would lock up with no error message.
All you have to do is change your screen saver from that one. As simple as that. You screen saver will not freeze after that.
Not all people experience the problem with this screen saver so I have no explanation why it did it to mine and your system. But atleats you know how to fix it.
Into my arms, O Lord