There appears to be no x86/x64 target for web site projects, only the Any CPU target. You therefore have to control the bitness of your website by controlling the bitness of your app pool.

On Windows Server 2008 or Windows 7, if you want to make an AppPool 32-bit, go into the IIS Manager > [Server Name] > Application Pools > Advanced Settings. Set “Enable 32-Bit Applications” to “True” for the app pool you want to run as an x86 process.

Note that you will have to take other WOW64 considerations into account, for example, registry settings accessed by your web app will now use the [HKLM\Software\Wow6432Node] key instead of the [HKLM\Software] key.

Courtesy of: http://stackoverflow.com/users/110776/nekno
URL: http://stackoverflow.com/questions/1883124/how-to-set-platform-target-for-a-asp-net-web-site-project

My solution worked for Desktop application and I am sure it should work for your web application too.

But I think here is your exact solution

http://stackoverflow.com/questions/1883124/how-to-set-platform-target-for-a-asp-net-web-site-project

I have the same problem i.e “The ‘Microsoft .Jet.OLEDB.4.0′ provider is not registered on the local machine.” error when I am running my code. I am using Window Vista Home Premium Service Pack2. I went to Build by right from the property of the project but couldn’t find for “Platform target” selection ComboBox. I need this for web application and trying in web application. Does your solution works for desktop application or both Desktop and Web applications.

Please Help
Kiran

What do i do to resolve this?