I recently downloaded updates to several mods. Soon after, Oblivion refused to start (frozen during Loading sequence).
After much tweaking I traced back the issue to three updates:
– Mighty Magick 4.5
– Arcane university revamped
– Cyrodiil Transportation Network
The issue with MM was resolved with a further update (apparently, I the update I first caught was corrupted when made available on TES source).
Issue with AUR and CTN were resolved by changing the load order. It appears they have to be loaded at the top of the list (soon after the official mods) in order for them to work.
Once again, the Oblivion Mod Manager is your best friend when dealing with multiple, often conflicting mods.