Does anybody know of a solid free registry repair/cleaner program?

You should always backup your Registry before working on it.

You can easily end up changing and/or removing more than you wanted to have happen.

"Generally" it is thought that "automated cleaning" the registry provides very little in the way of improved system performance...
And at the same time the automated process can be a high risk to your machine's functionality.
Therefore, it is not often recommended for the average user.

Know what you are changing or removing BEFORE you click to have the changes made.

Ccleaner "issues" is thought to be reliable
and
http://forums.whatthetech.com/RegSeeker_t104230.html

Be Careful.

A program I use is called Ace Utilities, but be warned with a program such as this could cause some harm if not used right.

http://www.acelogix.com/

The other program that I use is what listed above CCleaner

http://www.ccleaner.com/

Like Doug said, "Generally" it is thought that "automated cleaning" the registry provides very little in the way of improved system performance... And at the same time the automated process can be a high risk to your machine's functionality.
Therefore, it is not often recommended for the average user.

Know what you are changing or removing BEFORE you click to have the changes made.