Especially with lots of "integrated" OS came out. Like Windows XP SP2, or Windows Vista SP1, these kits seems to be forgetting adding some important DLL's to system...
If you think IE8 open slow? or tabs?
Try following given by one of member of me, I tried it even I didnt have a problem. It sure speeds almost everything up that uses IE or system to connect to internet...
XP users:
Start -> Run -> type following:
regsvr32 actxprxy.dll
And reboot,
Vista users:
Start -> type "cmd.exe" to your search line, and right click and "Run as Administrator" and type above code and reboot.
HuwR, that's not realted to IE8 installation, but OS installation :) IE8 installation assumes OS installed correctly and known problem for Microsoft since IE6 even :)