Greg;

Can you give more information about your incident?
Is only the NewsFeeds module affected by the change to .Net4.5?

Under which .Net version was the site running before upgrade?

Is this 6.2.3 Community or a different Edition?

When you look in the web site log.resources file is there an error or errors associated with the module in question?

Are there are errors in the Windows Logs Application or System logs regarding .Net 4.5 and/or the News Feeds 4.2.2 module?

Thank you,

Ken,

Yes, only NewsFeeds module was affected by the change of apppool from 4.0 to 4.5 .Net Framework. All other modules are operative normally and as usual. The break down occurred abruptly after the change and the refresh/recycle of the server, apppool and my website.

My site is powered by DNN 6.2.3 Community Edition.

As to IIS 7.5 logs I don't seen any pecular entry stating that there were errors concerning NewsFeeds Module unless the errors are coded.

Unless such an entry  from the log as the one below tells you anything (don't tell me by any chance that it has to do with module.css):

2012-10-01 17:34:32 192.168.0.101 GET /DesktopModules/News/module.css cdv=155 80 Greg 192.168.0.1 Mozilla/5.0+(Windows+NT+6.1;+WOW64;+rv:15.0)+Gecko/20100101+Firefox/15.0.1 200 0 0 22

But my site's Event Viewer - Log Viewer shows what follows: