MW cannot stop the spam from coming in the first place, (only your ISP can do this) however it does allow you to delete any spam/virus emails before they reach your PC, which is what it is made for.....
Re blacklisting, most spammers only use the same address a few times, so this makes blacklisting no good for most spammers, but it is handy for those senders who keep persistently sending the same emails.
Re Reporting, MW can only send the reports, if ISP's or whoever you report to fail to or cannot act on these unfortunately there is not really much you can do....
Another option is that you can setup MW to auto delete a lot of your spam.
To auto delete senders you have already added to your blacklist for example, click Settings>>Spam Tools>>Blacklist>>Options, tick, "Auto delete blacklisted emails".
You can also set your filters, (Settings>>Spam Tools>>Filters>>click a filter>>Edit) to auto delete by selecting this option under the Actions tab there...
And to set MW to auto delete any email that comes in over a specific spam rating, click Settings>>Spam Tools>>Spam Ratings, and tick, "Auto delete if rating reaches:"
Note however, I recommend you read this first before enabling the last option:
http://forum.firetrust.com/viewtopic.php?f=50&t=7214
Also, checkout some tips here on how to use MWPro to its best effect:
http://www.firetrust.com/en/products/ma ... and-tricks