updating for wave 3

hi all i am having problems with my xbox well a couple of problems really if any one could help or point me in the right direction !!!

i have 2 xboxs both modded these are my problems :

1. i have red ring on 1 xbox i have tried a few thing e.g the towel wrapped round thing it works for a bit then red ring again how can i fix it

2. my other xbox has been modded but not for wave 3 do i just need to " upgrade " or totaly re flash ?

sorry if the answers are all ready on another forum but looking is quiet hard at the moment as i have a broken collar bone !!!!

any help would be appreciated as bordom has set in