if u are going to do a clean install, it is wise to take everything ea, mohaa/mohsh related out of your registry as add/remove programs doesnt entirely remove everything. to get regcleaner, check out this link:
http://www.voodoofiles.com/523
be careful not to remove anything important, although w/ regcleaner it is self explanatory. reboot after removing named progs from registry and then do a clean install. hope this helps and good luck.
as for your other "blocky issues" im not to sure as i have never heard of that problem before.