Cool...in which case that makes it a wee bit easier....I do too.
Well, you're running ahead of me here.....did the MalwareBytes report have anything in it relating to 'www.com?'
If so, where was it?
A file?
The registry?
Did it quarantine everything it found?
Did you save the report?
Can you post the report?
You could try as Sam said and change the homepage back to what you want via the about:config but without knowing if the cause has been found and dealt with there is no guarantee it'll not change again....probably when you re-start FF.
How to:
Method #1: Tools > Options > General change homepage.
Method #2:
Type about:config in the address bar of FF...hit enter or whatever.
Accept the 'dragon' warning...if you get one.
You'll see a search bar at the top.....type: 'www.com'
The list should filter out everything not containing 'www.com'
At least one of the items left should be:
browser.startup.homepage
Double click this (or right click and choose 'Modify'), and change it to what you want.
If there are any more entries with that text in it make a note of them and post them here.....unless its blatantly obvious what they are in which case change or delete them as you see fit.
If you are unsure post the affected preferences here.
See how that goes.
Regards.
MrTom.