You should be able to get into safe mode by whacking F8 when you get your boot menu, and then selecting it from the list.
Whichever services you chagned to automatic you should set back to manual, if the system needs them, it will load them itself automatically when it boots.
I've messed up my services before now, changing some of them has really weird effects, strangley enough the worst one to remove is event log, if you dtop that everything goes completely tits up.
Check to make sure that it's still enabled
Hope this helps
