Restoring registry backup

I apologize that this is such a silly question, I'm not very knowledgeable about registry editing and don't want to destroy my system.

I would like to restore a backup of the registry I made with CCleaner several weeks ago, but am hesitant because of the following:

1. There are two registry backups, and I want to restore both; I'm assuming I should restore/merge the last one I made first and then the previous one next, right?

2. Does it matter that I installed a new program since the backups were made?

3. Does CCleaner backup the entire registry or just the entries that it fixes/deletes?

Thanks in advance! I hope these questions weren't already answered somewhere on the forum and I failed to see them earlier.

1. Yes

2. It shouldn't

3. Backs up just the deleted entries, not the entire registry

Has CCleaner caused a problem on your system that has prompted you to reinstate the backups?

Thanks so much for the info JDPower. :)

I am not sure if CCleaner is the cause, but I used it right before I started getting blue screen stop errors (pointing to the Panda driver RkPavProc.sys) each time I attempted to run Panda ActiveScan. Then again, I haven't used ActiveScan in a while so I don't know when the issue appeared. I'm trying to rule out CCleaner and see if the errors do not appear when the registry is restored from the backups.