Windows 7 Home Premium
ccleaner build 3.07.1457 but has been happening with all the versions since February when I got the computer, I always use the latest ccleaner, (that is how long it has taken me to pinpoint this to purely a problem with ccleaner, at first I thought it might be a fault in the manufacturers driver software)
Yes a normal (no advanced options) registry clean, no issues before doing it, just to try and improve performance of the computer.
security software on my computer Norton 360 but problem also occuring on my sisters computer same make and model but she uses microsoft security essentials.