2 things which are extremely important:

1. What were the wad files that you used in step 2 which you uninstalled (I am guessing the ios stubs but no idea).

2. What was the error you got during the installation of cios.

Several other things to ask:

3. Random freezes; Please explain more, during playing original games or backups or USB HDD or what?

4. Have you backed up your NAND after step 1? Decent guides should always recommend this before sending you to uninstall IOS files as you can potentially brick your Wii and without a NAND backup you leave yourself with a major headache to get your Wii working again.

If you did not back up you NAND, head straight into Bootmii and get yourself a NAND backup before you answer my questions