IIS Error- Retrieving the COM class factory for component with CLSID {00024500-0000-0000-C000-000000000046} failed due to the following error: 80070005 Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED)).

For this fallow the fallowing steps-

 Enable the ASP.NET authentication for default website (in IIS) then create Desktop folder at C:\Windows\System32\config\systemprofile\Desktop.

step1 :  Go to run type dcomcnfg 
Step2:   Click >Component services >Computes >My Computer>Dcom config> and select microsoft Excel Application> 
Step3:   Right Click on Microsoft Excel Application>Properties>Security Tab
Step4-Under-Launch and activation permission->Customise->Edit->Add--type-(IIS_IUSRS) 
-> ok -> Allow Permission-Local Lounch and Local Activation
Step5- Repeate Step4 for Under Access Permission

Reference--http://www.youtube.com/watch?v=ijfb3E_7t3o