With a little bit more tinkering, I've solved the problem. Although I couldn't find the framedyn.dll the first time I searched for it, I rebooted and tried again, locating it successfully! After copying it to system32, I'm happy to say everything is back to normal.
I can't imagine what happened to cause the problem in the first place as I've hardly used my PC in the last couple of days and only visited the same sites I normally do (no problem prior to then). But problem solved, end of!
Thanks again for your help; much appreciated!
This thread is now locked and can not be replied to.