I had problems with my SP2 update as well.
Every boot after I installed it, my computer would take 10 min to boot, instead of the usual 2. After it booted, my printer would also fail to work. IE (i dont use it, but my parents do) also had some major problems. Also, if i atempted to access my hard drive through the My Computer icon, explorer.exe (as in windows, not IE) would crash. I hadto make a shortcut to access my HDD. Eventually I just uninstalled it. I tried it again a few weeks later, but had the same problems. A friend of mine (who isnt very computer literate) also had similar problems on her laptop, although i dont know what exactly. She also uninstalled it.