I have looked at the FAQ here and I searched the forums but I couldn't find anything, so here it is.

I have decided to play Oblivion again, and I have done a clean (I hope) installation of Oblivion, but when I start it up, it won't load. I installed SI and FCOM (plus the UOP and USIP) before I even played, so I suspected the mods to be the problem. But when I unchecked FCOM and the unofficial patches, Oblivion still didn't start. So now I don't know what to do. Anyone have any ideas?

Documents/My Games/Oblivion/Oblivion.INI

Delete that file (configuration settings), and try again.

I tried that and I am pretty much in the same situation that I was in before. Originally I froze whenever I pressed space to skip the opening Bethesda screen so I used Wrye Bash to disable the opening cutscene, and then I froze at the loading screen. Deleting the INI has now brought me back to freezing at the opening sequence.

What did you use as a guide for installing FCOM, TESIV:POSitive, the release thread in Oblivion Mods for FCOM Convergence and UFCOM, or the FCOM website that is outdated in information and working links? I am reccomending following the instructions in the release thread in Oblivion Mods, it is the most current and up to date, no offense to Tomlong.
I hate to recommend a fresh reinstall of Oblivion, but you may need to if you used a manual install.

Heh, I guess I used an outdated install guide. I used http://devnull.sweetdanger.net/fcominstall.html.

I made the same mistake myself when I first installed FCOM. Be sure to get the most updated esp's from the MMM and OOO threads when you begin your rebuild, and good luck!

So will I have to do another clean install? And can you point me to a good up to date set of FCOM install instructions? The last time I played Oblivion I had a lot of CTDs, so now I want to start fresh with a stable install of FCOM, and then build off of that.

The official FCOM thread is down in the Mods forum; the most up-to-date info is there. Read the OP and it will tell you everything you need to know.