critical error message pop up

I am getting some critical error messages registry damaged and corrupted to solve the issue open internet explorer and type registrycleanerxp.com. The other pop up ask me to go to - scanpcnow.com, msreg.com and clear32.com. Does anyone know whether this sites are genuine? I also know that if I will go to this sites, then they will offer me to purchase this packages? Any ideas?

I dont think any of the sites that you have mentioned are legit. Have you got Windows XP with SP2? Have you also turned on the Firewall and is the Messenger service is disabled?

I would recommend you to run a malware scan in your pc using Spybot and SuperAntiSpyware. You can download the same from their official website.