COGNOS 10.2.1 issues where .NET 2.0 and .NET 4.0 is installed

[tradeex]

Hi -

We have several applications running on same server that required .NET 2 but now have a new app requiring .NET 4.0 version as well. After installing .NET 4.0 on the server, cognos 10.2.1 stopped working. I get an error when trying to start Cognos service now and the error is:

[Content Manager database connection]
[ ERROR ] The database connection failed.
[ ERROR ] Content Manager failed to connect to the content store. The connection string is "jdbc:oracle:thin:@10.3.201.32:1524:COGTEST". The error encountered is: "Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
"

After installing .NET 4.0 the db caused an error and now DB is not working and is giving me an error:
Listener does not currently known of SID given in connect descriptor.

After install yesterday, Cognos did work but caused different errors and was not able to run cognos reports.

It gave 'handler' error initially.

Any help would be appreciated.

Thanks,
Petra