Have you got Microsoft .NET Framework 3.5 SP1 installed on your PC? If so go to Add/Remove click on 'Change/Remove' and when the .NET Framework panel comes up select 'Repair'. If you haven't then you need to download it from MS Updates.
If you have trouble with MS Updates it is likely you don't have the ActiveX installed. Use the link click here and if it asks your permission to install it accept.