I have been monitoring other forums, neowin being one and there are tons of threads about problems with SP2, some about slow boot times.

I doubt that they are all using avast.

The SP2 update is a huge step forward and like XP broke lots of things, with some software and hardware not compatible. The same to a lessor degree is likely to be true with SP2.

It is estimated with an update this huge if they only have a 1% problem rate, it will still effect millions of prople. The permutations of peoples systems, software, hardware is huge.