Using Vista Home Premium 32 I unistalled Norton Security but it has left behind registration entry: cc_20071101_2027 Can I safely delete this?
Probably - if you are 100% sure it belonged to Norton. But as always, make sure you backup the registry before making any changes to it.
I have had problems with broadband connection dropping out and BT used remote assistance to check out my settings. By typing 'norton' in search this item appeared, so presumably it does refer to Norton. How do I back up registry? (I know I should know but I have never yet had to, sorry).
To back up, open Regedit and ensure My Computer is highlighted in the left panel. Then click File > Export and follow the prompts to save the file. Restoring uses the reverse process, except you import. Alternatively, ERUNT is a popular registry backup/recovery program.
I did that and a message says that the file already exist and do I wish to replace it. I am really lost here!
That just means you did this once before and used the same filename. If you don't remember doing it, then it was probably awhile ago and it is safe to overwrite it. If you want to keep it anyway, simply enter a different filename during the save process. You CANNOT hurt anything by exporting.
It turned out to be an 'orphan' which I deleted and now all is well. Simple, huh? - When you know how.