I too have a problem with my Wii. I'm sorry to expose it here, but I hope someone could help me.
I wanted to install Preloader and make use of some of those system menu patches;
so I run first "hackmii" and installed dvdx, latest version of homebrew channel and bootmii in both of his versions.
I then installed Preloader, but after I installed it I couldn't access the system menu anymore; only Preloader menu, homebrew channel e bootmii
I then decided to try to uninstall Preloader... so I took the v480 system menu (Japanese v4.2 - My Wii is/was japanese) wad and tryed to install it
but it gave me error... so, thinking it was the right procedure, I "uninstalled" the wad and then re-installed.... this time it didn't give me any error.
But when I rebooted my Wii it got completely black and Wiimotes didn't sync anymore. I have a GC controller though.
So I am now in this situation:
-I have no NAND backup 'cause the SD card I was using wasn't big enough to contain one.
-I have an old Infectus mod chip on.
-I can run Bootmii but no Homebrew channel (it goes to a black screen).
-I can run .dol files using CBoot2 but I can use only those that don't need the wii remote.
I tried reinstalling system menu files like 4.1J 4.2J 3.4J
using the modified Wad Manager and Dop-IOS
They seem to install fine (no error) but the system menu still won't work.
The Bootmii info page gave me these readings:
-Bootmii v0.9
-stub v1.1
-mini v0.9
-Sysmenu: unknown boot1b boot2v4
-NAND FS usage: 79.1%
The ios I have installed are (I list only the ones I think might be important, but if needed I have written down them all):
IOS36 v3351 (it should be patched)
IOS60 v6174
IOS70 v6687
IOS222 v4
IOS223 v4
IOS249 v14
IOS250 v65535
IOS254 v31338
I got this info from Dop-IOS.
I would be glad if someone could give me an advice. Sorry for using your time.