If when you hacked your Wii you were on 4.1, there was no IOS58 at the time and the Homebrew Channel would have decided to run on IOS61.
Running HBC on IOS58 gives it access to the Nintendo USB2.0 module for faster reads from USB.
Installing IOS58 won't delete HBC, it just makes it faster, you don't need to delete HBC to re-install it. Some apps will only load if HBC is running on IOS58.
Launch HBC and press the Home button, in the upper right hand corner it will tell you which version you installed and the IOS it is using. If it is any IOS other than IOS58, you want to reinstall it.
Any good modding guide would have had you install IOS58. You can either run
Syscheck or look at your wad folder to see if it was installed.
Modmii or the "Guide: Softmod ANY Wii" originally wrote by Mauifrog are both good.
You have a couple of options to reinstall HBC:
With the HBC still installed, make it an app to load from current HBC:
Take the boot.elf from the Hackmii Installer and put it into a folder called Hackmii Installer and then put that into your apps folder on SD. SD:/apps/Hackmii Installer/boot.elf
Now when you launch HBC there will be an app called Hackmii Installer, load it and run the Hackmii Installer again to reinstall HBC.
Reuse Bannerbomb:
Put the private folder along with the boot.elf from Hackmii Installer back into the root of your SD card. When you click the SD card icon from the Wii Main Menu you'll get that same popup asking if you want to load boot.dol/elf click yes.
Use an app with an App Loader in it:
Both
Wiimod and MMM (Multi-Mod Manager) have an app loader built into them. It's been a while since I've used either to load an app but it can be done. USBLoader GX also has an app loader.
Use a forwarder channel you already installed:
Most guides have you install a forwarder channel to launch a USB loader without having to go to HBC first. If the forwarder is looking for any of these, (or you know where it is looking, a forwarder for any app will work)
FAT:/apps/usbloader_cfg/boot.dol
FAT:/apps/usbloader/boot.dol
FAT:/apps/usb-loader/boot.dol
FAT:/apps/usbloader_gx/boot.dol
move or rename the boot.dol temporarily and put the boot.elf from Hackmii Installer into that folder. When you use the forwarder channel (with boot.elf in place) it will launch the Hackmii Installer. Once you are done put the original boot.dol back in place.
The first two option are probably the easiest