Need help with Registry EditorFollow

Yes, I am an idiot.
Today I decided it would be a good idea to go into the Registry Editor and change a few things to make the game look better. I swear I followed everythong in order to for it to work but alas, my computer disagrees.
I have not made a backup and I feel as though I am the biggest idiot right now.

Final Fantasy XI will not start up. I select play on the PlayOnline svreen and the screen goes black, only to redirect me back to my desktop with the error; "Terminated as error occured in FINAL FANTASY XI. Failed to initialize Direct3D. Please check that this computer has the required specification to run FINAL FANTASY XI.(-1)"
It was working perfectly until this incident.

Anybody got an idea on what to do?
I am up for anything, I just want my FFXI back... :'(

One common cause of this (apart from DirectX problems sometimes found when installing the game for the first time and not likely in your scenario from what you say you did) is the game trying to set the display resolution to something the display can't do. It's some time since I got it so I can't be more precise than that. Check the registry entries that set this; these are the 0001 and 0002 entries, while the 0003 and 0004 are the render buffer size and a mis-setting of those won't cause this AFAIK.

If you're fiddling with the make sure you're setting them in DECIMAL not HEX, that's one easy mistake to make messing with this stuff, do it wrong and you end up with values your monitor can't accept and the DX runtime failure message results.

If you're still stuck go back into the FFXIConfig program, set the values it allows and exit, in my experience that will reset the registry to sane values.

These are my entries running on a display of 1920x1200:

"0000"=dword:00000004
"0001"=dword:00000640
"0002"=dword:000004b0
"0003"=dword:00000c80

These values are in HEX as dumped by REGEDIT.

Edited, Apr 26th 2012 10:52am by Kragorn

Yeah, just do a System Restore in Windows back to the day before you made the changes (or the first available snapshot before the changes happened if there's no back up on the day before). It won't delete any data you have saved but if you have recently patched Windows, it will remove those patches. So do a System Restore, then run Windows Update to make sure you have the latest patches and you should be good to go. Oh and stay OUT of the registry unless you really understand what you are doing if this computer is important to you. If it's just a gaming rig (not he family PC with family photos, financial data, etc), have at it. Worst case there is you have to reinstall everything. You don't want to have to do data rescue on a computer that won't boot.

Generally okay advice, but given SE have never made the FFXI Config program capable of making the settings such as the buffer size vs. display resolution as anything other than total CRAP then sadly registry fiddling is the only way to get the game looking at good as it can be .. which is a LOT BETTER than FFXIConfig lets you do. :(

Wow thanks for all the help guys!
I really appreciate it!

I'm going to begin a system restore and see if that helps the issue.
I'll be sure to post here if it does/doesn't.

Unfortunately, the System Restore did not work :(
Getting pretty desperate here as nothing seems to be working...

Help!
I can give any info of my computer you desire.

Glad you got it sorted! Mind telling us how you fixed it, in case anyone has a similar problem in the future?