In SeaMonkey after installing AdBlock plus, do the following to remove flash completely.
Open AdBlock plus (Go to tools > AdBlock plus).
Now click the filters menu and select ADD FILTERS.
Now in the filter rule type *.swf and click the apply button.
Here after you will not be able to view flash in your browser. Blocking flash helps save a lot of bandwidth.
If you want to see flash in a particular page then you will have to disable AdBlock plus by going to AdBlock plus > options >and uncheck the Enable AdBlock plus menu.