So at some point after CS4 was installed (may not be the culprit, but in other threads related to Tiger and the same issue, CS3 was mentioned), my screensaver will not lock the screen on 10.5.6 (from iDeneb).

Any ideas? I found a link on another thread elsewhere that recommended switching it off, deleting a .plist or two, rebooting and setting it back on, but I don't recall that working, though I may not have got it quite right.

Another potential culprit? Logitech Control Center. I got a DiNovo Edge for Mac keyboard for my Hack (BEAUTIFUL keyboard, btw, both for usability and looks). LCC does some OSD stuff, and around the same time, I noticed that at least one (I had only just gotten it, so don't know what other OSD stuff it should do) OSD had stopped, for Caps Lock.

Would be nice to be able to lock my PC Any suggestions?

Bump?

Solution: I created a new user, and copied their com.apple.systempreferences.plist over to mine, changed ownership and logged in again. Voila!