I split your post from the original location that you posted to and moved it to the Install topic folder of the forum. The original thread was unrelated and was over a year old.
To see if OneCare is the cause of the slowness in IE, try disabling the firewall and virus/spyware protection of OneCare, first together and then one at a time.
One cause for this problem is that you are using a custom Hosts file, perhaps placed there by other security software. It can also be due to security software remaining installed and active on the PC. All other active security must be removed if you are using OneCare as multiple active protection products can cause slowness and system instability.
You may also want to try running IE without any add-ons installed - toolbars, etc. As it may be a problem with an add-on.
You can contact OneCare support if you determine that OneCare is at fault for the slowness or if you are unable to resolve it.
How to reach support (FAQ) - http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/30400b52-7f26-4ba0-bc18-17e305329d90
-steve
Microsoft MVP Windows Live / Windows Live OneCare & Live Mesh Forum Moderator