OK...
Short and sweet......it works
Let me explain
After above posting, I went back to what I had done, to make sure....
I had actually 5 installs in 2 different paths
First
/mnt/image/Virtualbox/
.VirtualBox/HardDisks/.......a few VDIs
Vms in this path gave me no full screen , either as user, nor as root
Except : Winxp.....no problem
Second
/mnt/image/Vbox.......a few VDIs
VMs in this path gave me no full screen as user, but they gave me full screen as root ? ? ?
Hmmm.........didn't know what to think...
So, I decided ( before the big Wipe ) to install in the /home/xena/.virtualbox folder.
I had to make space for this as my home folder was fairly full
When I clicked on the VBoxLinuxAddition.run file to run as root, a windows popped up telling me
that it wasn't happy because it found files which didn't belong there and if I wanted to continue
I said yes...... and I cut it short....after a reboot it worked
So, what have I been doing
before. What was so different ?
Well ,
every time in previous installs, when I wanted to run VBoxLinuxAdditions.run a window popped up
asking me for a password. I gave the password, then there was a second of activity, and then nothing.....I waited a while, and because nothing further happened, I was convinced that ...that was it.
More over, because when I clicked full screen in some installs, it really went to what was a full screen, but the actual screen of the distro stayed small.
So, I was convinced that addition were installed ( as the screen went big )
So, I executed VBoxLinuxAdditions.run as root
again.....wait....wait....ask me for my password.....
wait....wait....wait....wait....waited 3 minutes. Nothing happened.
So, I decided to run 'autorun.sh' as root
Click, password, ....wait...wait...wait....Ah...there it goes
But I had to wait for about 2 minutes ( as in 120 seconds ).That was the Full Monty
A normal user certainly would have moved on already
Anyway...after a reboot it worked
I went to all other installs which didn't work before and it was the same story.
Wait at least 1 full minute ( as in 60 seconds ) , sometimes longer.
In short....running VBoxLinuxAdditions.run as root never worked.....but autorun.sh did.
Now, I had seen autorun.sh before, and I guess I knew what it was, but for a reason
totally beyond my understanding, I never used it..till now.
I have checked all VMs, except the kiddies one ( as there is a Keyboard problem )
So, thanks to all and
specially OP.
There still is something wrong, but we will see about that later.
The change over from Full to narmal to Full is everything but smooth.
But I can live with that...for now
Again, my thanks
I owe you one
Now it's bedtime. Have spend over 12 hours on this.....

Xena