I can't access to my site after updating wampserver (1 reply)

Hi,
I updated Wampserver and all the programs. The icon is green and I changed the versions of the databases - I should see the log in page for wordpress when I type localhost on the search engine, but I get this message instead:

Can’t select database
We were able to connect to the database server (which means your username and password is okay) but not able to select the mysite database.

Are you sure it exists?
Does the user root have permission to use the mysite database?
On some systems the name of your database is prefixed with your username, so it would be like username_mysite. Could that be the problem?
If you don’t know how to set up a database you should contact your host. If all else fails you may find help at the WordPress Support Forums.

Please, could anybody explain me what thing I did wrong and how to fix it?

Thanks for your time.