Problem with Windows Installer

Hello, i am Wayne and new to this site. My computer has started to give the following message from boot up. It opens a window saying "preparing to install", this happens 5 or 6 times, then another window appears saying " Microsoft .NET Framework". In the information panel this long message appears-" An unhandled exception has occurred in a component in your application.Click continue and application will ignore this error and attempt to continue. Object reference not set to an instance of an object.

In the detail section there is a huge list ending withthis message.

When JIT debugging is enabled,any unhandled exception will be sent to the JIT debugger registered on the machine rather than being handled by this dialog.

Please excuse my long winded explanation, i dont now much about computers and would look foward to any help, many thanks Wayne.

 

It is just telling you there is a problem with a program/application and that the debugging tool (JIT)for .net framework is not installed.
This can happen when running an application on other than the one that wrote the app.

http://en.wikipedia.org/wiki/.NET_Framework

How to install JIT
http://msdn.microsoft.com/en-us/library/k8kf6y2a(VS.80).aspx

Have you installed any new programs/apps right before this started