System symptoms of GPU artifacting.
Anyway the same way Bootmii/boot2, HBC and DVDX were installed they can be uninstalled. Those options are given during the installation process. Just keep all your Brew applications on SD and do the same for any unofficial channels. You'll have to re-install those anyway if you get a replacement system. Then if you don't have the new official update 4.1 get it if you dont want to format your system memory and want to keep all your playstats etc. They might send you a replacement system. Thats what they did for me earlier this month for the same problem.
This is almost like you're preparing your Wii for a piss test. *L*