rb45 is right. Do NOT go to any of those linked sites.
Google up the registry cleaner mentioned above, or the free one that I use, RegSeeker. (You should have and use one anyway.)
Then you need to get rid of the malicious bug that's causing those popup notices about a registry problem. There are several good spyware removers for free or low cost. Many people use Ad Aware or Spy Bot. Microsoft will give you Windows Defender. All these are in ADDITION to a good virus protection program (Norton or McAfee) and a good firewall (Zone Alarm)! You need them ALL to be even partly safe these days!
Some you can buy or download from known safe sites (go DIRECTLY to the host site URL, not by clicking on a link). Search sites that test, review and recommend freeware or shareware (Tucows.com is excellent) for a product that you like.