I am having the same problem. I have detched EVERYTHING.
I have even switched to test female avatar.
I even deleted the phoenix viewer and reinstalled.
I even tried two other viewers. Nothing mattered.
I switched out my keyboard. It did nothing to help.
I cannot control my avatar.
I even re registered and set up a NEW avatar and the same thing happened.
She shoots up into the3 sky.
the page down lowers her a bit but she springs right back up.
The stop flying sometimes drops her for an instant but she springs right back up into the sky.
There is noithing I can do.
The problem has been going on for a week.
I am about to give up on SL completely.
I cannot get ANYWHERE and nobody seems to be able to help.
HELP!!!