Several points to answer here so here goes..

1) Free Wi-Fi is spotty for a lot of people and depends heavily on
line of sight to a transmitter plus number of users hitting that
particular node. You might need to experiment with location in the
apartment / house to find which areas get the better signal !

2) You have a dual core P4 evidently - each core shows up as a
separate processor.

3) Not a good idea to go messing with priority numbers and many
processes will reset to defaults anyway. Multiple Firefox ones isn't
unusual !! Most will show as 'sleeping' because they are waiting for
something to use them - saves having to load/unload processes on the
fly.

4) Ubuntu does not suffer from malware / viruses .... period