the proces cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020)
After bit of googling I found, Skype by default listens/uses port 80. Because of IIS also listens on port 80 by default for http traffic, there is conflict between Skype and IIS.
Solution: Quit the skype, Start the IIS service, and Start the Skype again!
One more thing you can do:
Open Skype >> Tools >> Options >> Advanced >> Connections >> Uncheck the checkbox which says "Use port 80 and 443 as alternatives for incoming connections", and click Save.