I have 4 user accounts in my system. And im only capable to allow 'extra' visual effects in one account at a time. I.e. if 2 accounts are logged in at the same time only one account will be having 'extra' visual special effects allowed. If i try to enable on the other i get a message i cannot do that.

And if i log out from my account which is using 'extra' visual effects enabled, then i can allow 'extra' visual effects on the other account.

System specs:

core2duo E8400
ram: 2GB
lspci | graph VGA
01:00.0 VGA compatible controller: ATI Technologies Inc RV505 CE [Radeon X1550 64-bit]
Restricted drivers are not listed at 'system>admin>hardware drivers'

Any help would be really valued.Thank you very much.