There are plenty of web resources available that discuss the syntax for registry entries as a quick google search shows
A couple of sites
If you try to create/amend/delete then you will need the correct permissions. eg the users group has only read permissons and cannot delete values for that key. To delete, you'll need administrative privileges. If you are using vista and above then even if you are logged in as administrator, you'll still need to obtain administrative rights before you can delete.
NB As this is not really a Visual c++ programming question and this is an 8-year old thread, you might be better off with the General Developer Topics/Windows OS Issues forum. [Moderator?]