!!! Services not starting: SOLUTION INSIDE !!!
Update Rollup 5 killed our SBS 2008 server.
After installation, the system "hung" at Applying Computer Settings... during boot.
After 1.5 hours, the logon screen appeared, but most of the Exchange services were not started.
We fixed all the config files by adding the <generatePublisherEvidence enabled="false"/> line between the <running> tags, but it didn't fix the problem.
Killing all processes and removing Update Rollup 5 didn't fix the problem as well, so this really got me thinking. Boot still took abount 1.5 hours before the login screen appeared, and moet of the Exchange could not be started. Exchange AD Topology was complaining that it couldn't contact AD, while it's on the same box! (it's SBS).
Finally, after 3 days of digging, I found the most simple solution wich I will NEVER forget:
Enable IPv6 on the NIC, and everything worked like a charm!
...and no, I'm not going to reinstall UR5.