I had a fear that things would not be as easy as you made all them out to be.
I installed 5 as you all suggested and avast says the installation is complete but I cannot do any scans.
When I click on the scan tab in the left side bar I get 4 rectangles that are completely blank save for the icons on the left side of each. No controls and no way at all to do settings or start scans and cannot locate any way to turn them on. Tried a repair without success. Even worse, after using the restore point created during the install, 4.8 is nowhere to be found. Using safe mode and reverting to a restore point made 1 week ago is no better as what remains of 4.8 is apparently not enough to get it running.
The rest of the GUI seems to display and work properly.
The system is clean; I hope some of you have some suggestions!!
(I year old custom built laptop with XP Home sp3, intell duocore processor, 2 gb ram 160 gb hd, Comodo 3.14 firewall, Spywareblaster, Malwarebytes, regular online scans with ESET, and Sophos)