Important: Do not download msvcr80.dll from a "DLL download" website. There are many reasons why downloading a DLL file is a bad idea. If you need a copy of msvcr80.dll, it's best to obtain it from its original, legitimate source.
"I did a search and all suggested I run some register checker which I did and to resolve this they then ask you to buy their software "
I am pleased to see you didn't use that option.
This is a description of it - msvcr80.dll is a process associated with Microsoft Visual Studio 2005 from Microsoft Corporation.\r It is the Microsoft C Runtime Library and is used by programs written with Microsoft Visual Studio 2005 It is not a critical component.
You haven't said whether it is affecting any of your applications or it is just an annoying error message that is popping up ?
Assuming your windows is installed in c:\windows Find the dll on your computer and copy it in the windows\system32 folder. Open a command prompt and type CD C:\WINDOWS\SYSTEM32 (if not already there) REGSVR32 MSVCR80.DLL
Or alternatively download and install this from Microsoft - click here