Does it freeze for a short time then unfreeze?
It sounds as if you have something interrupting it. If this were me, I'd assume malware of some kind.
Everyone has their own favourite suite of programs for these generally difficult situations. Mine are:
http://www.bleepingcomputer.com/download/rkill/ First You get a log from this, you could post it here.
http://www.bleepingcomputer.com/download/adwcleaner/ second.
http://www.bleepingcomputer.com/download/malwarebytes-anti-malware/ Third. (Remember to turn on rootkit detection)
If all else fails, this: http://www.bleepingcomputer.com/download/combofix/
read the following to see if you really do need a registry cleaner:
Courtesy of PA Bear:
TIP: If you ever again think your Registry needs to be cleaned, repaired, boosted, tuned-up, cured, tweaked, fixed, maximized, "swept" or optimised (it doesn't), read http://chris.pirillo.com/are-registry-cleaners-safe-to-use/
and/or
http://www.edbott.com/weblog/2005/04/why-i-dont-use-registry-cleaners/
then draw your own conclusions. Also see
http://blogs.technet.com/markrussin.../02/registry-junk-a-windows-fact-of-life.aspx
Good to hear koolx.
Can't add anything to Elizabeth's answer.
The registry is one of those issues, rather like brain surgery and the moods of women. You know they are there but best leaving it to the brave and the skilled.