Cannot Publish because a project failed to build

Hi,

I had a project written in VS 2005 which worked fine.

Laptop updated to Vs2008, when I opened the project it asked to be convert the application.

I clicked Ok and the application converted.

Tried to publich the application I receive two errors;

- 1) Cannot publich because a project failed to build
- 2) An error occurred while signing: A certificate chain could not be built to a trusted root authourity.


I tried:

- Uncheck - Sign the ClickOnce manifests in signing tab and publish
- Uncheck and check the sign the clickonce manifests in the signing tab (Note: I dont want to create a NEW test Certificate for a year - I have a certificate already created to expire 2028)
- On security tab - tried to uncheck the Enable ClickOnce security settings

Note: when I build solution from the tab it works and builds successful.

All these prompted same errors..

I never used to receive these errors ONLY after updating to VS2008 and conversion.

Any help please
Thanks