Slow performance in SDL TRADOS 2011 - segment confirmation

I  own the SDL TRADOS 2011. When I press Ctrl+Enter in order to Confirm and Move to Next Unconfirmed Segment, the cursor is changing to circle and it takes ages to move to the next segment. And the Studio is not responding.

I do not have any anti-virus program that would slow the preformance, as I have read in some related articles.

Do you have any idea on how to resolve this issue?

Thank you in advace