If you are able to turn on the OneCare components manually, I suspect that there is a conflicting program on your PCs that is causing the problem. Did you completely remove your prior antivirus program? Are you running any other protection software?
Slowness of OE and any other programs with OneCare installed also points to a conflict with other security software. Note that OneCare does not scan emails inbound or outbound.
For your 3rd issue, since OneCare does not scan email and Outlook Express is already being allowed access to the Internet, it may be a security setting in OE or, once again, a conflict with other security software, or an OE problem.
I recommend that you contact support.
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
-steve
