I usually just use the NSU on the computer I use for updates, no other nokia software is installed on it. I've never had a single failed update on that PC.

However some people have said that certain updates have only been available through the ovi suite but I can't confirm that.

It does always have to be the latest version of ovi suite or NSU for it to work.  

If you have a computer that has never been 'tainted' by say the Nokia Suite, or any Ovi beta - feel free to use the Ovi suite - updates and syncing work fine, much better than the old nokia suite.  The reason I say fresh is that i've had problems where not eventing seems to get removed from the Ovi betas or the Nokia Suite.

Here is the procedure that works for me:

- Copy everything off your phone (or sync) music, contacts, photos, videos, etc. (if you sync your contacts with say outlook this makes it REALLY easy.

- Install the new firmare

- Flash your phone.

- Set messages to store on 'Mass Storage' right away! 

- Copy or Sync everything back.

- Reinstall apps (put them on Mass Storage) 

Most people skip the Flashing part as they don't want to loose apps etc.  In my opinion unless you want to struggle with your phone and C: space issue forever - just Flash it and get it over with.  makes a world of difference.  Just do it!

By Flash I mean resetting it so that everything is back to defaults - removes everything like it came from the factory with the cleanest lastest OS.  This leaves mass storage in place, so if you have apps and stuff on there it will be OK.

you can do the 3 finger salute:

Turn your phone off AND simultaneously press these four buttons circled in red.

Caps Button

Space bar

Backspace button

On button 

' I think that´s called a "Hard reset" '

Nope, its called the three finger salute.  Not to be confused with the one finger salute I am giving you for questioning me!

Just kidding. You are correct - it is indeed the hardest reset of them all.