Apps and FW Upgrade??

I'm just curious to know about if I have to reinstall all apps after a fw upgrade/downgrade/reinstall.
Some programs (if not most) set paths in the windows registry and this is reinstalled on a new fw...so aren't all regstry paths reset on a clean/upgrade installation?
That would most likely mean that some programs aren't going to work after an upgrade? ... or lead to corrupt/invalid registry paths?

Is it best to delete all the programs in the 'Disc' folder.. upgrade.. and reinstall all apps again? Or is there a simpler, cleaner method?

a fw upgrade/downgrade/reinstall resets everything except the "disk" that means registry and so on.
I think programms will still work unless the firmware u upgraded/downgraded/reinstalled doesnt work with the app.
If i'm right about the progs u could use M8sprite to set new desktop icons.