Camera movements stop when using ALT key during mouse movement

Hi,

I'm having trouble with camera movements stopping every 2nd time I move the camera. What I do is:
- hold ALT down
- move the mouse
- every 2nd time I only get the first fraction of a second movement then after this when I keep moving the mouse the camera does not response (at this stage I still have the ALT key down)

I have to then repoint at an object, hold down ALT and move the mouse to try again - quite frustrating.

Any ideas?

PC DETAILS = P4 1.6GHz, 1.2GB RAM, with ADSL internet (obviously not the most powerful PC, however besides this issue I'm happy to use it for scripting/building etc)
VIDEO CARD = Gigabyte N55256D FX5500 256mb 128BIT AGP8X DVI-PORT TVO TwinV
(just bought the video card a couple of weeks back - havn't tried to do a software update check yet)

Regards
Greg

When holding the Alt key, the camera inevitably has to pivot around an object, avatar, or ground that you click on. Sometimes, when you click drag while holding the Alt and point at the sky or something too far away, the camera will not budge.

Also, if you want to rotate around your avatar while moving using the WASD keys, you can just click and drag on your avatar name bubble.

If it still doesn't work, check your mouse double-click timing and also the 'sticky keys' settings in the windows control panel.

I'm quite used to what correct operation is on another PC. This is not the issue in this particular case.

Can't see how it would be double-click timing as I only "single-click" on mouse button(?). However the sticky keys settings sounds worth checking out, I'll check on this - although why would it work sometimes and not others(?) - I'll report back.

Tks for responding

I have no idea Greg. I'm just shooting fish on the moon with a pop gun.