Internet Explorer problems after SP2

Hallo everyone!
In my computer, well running with SP1, I downloaded SP2 with these results:
a) IE is no more able to browse; the only way of browsing is using MSN
Explorer, not able in any case of accessing Windows update;
b) the only way of stopping remote connections is through the computer'stop,
otaining in any case the message that "Connections tray" service has to be
stopped manually.

Any ideas coming from the super experts? MS support seems not aware of
similar problems, at least in Italy.

Many many thanks and mille grazie. Carlo