Re: How to delete tasks in QV management console ?
And regarding your other questions:
The Source Documents tab only appears if you have a Publisher. Without a publisher, there is only a User Documents tab, and all suggestions apply there as well.
In v9 QEMC and QMC were the separate identities of the current QMC. Ever since v10, there is only one Management Console. Indeed it doesn't matter for you.
As Ashfaq says, create dummy documents with the exact same name and in the exact same spot (subdirectories are important!) as the deleted documents. The documents can have a 0 bytes size, so this can be done with Notepad. As long as you rename the text files to something.qvw.
After that, check your User Documents tree. The deleted documents should have reappeared, including the missing tasks. Delete the tasks (and any Document CALs you may have assigned to those documents, or they will become lost too) and then remove the documents. Now, the Task overview should reflect a correct situation.