Green Sprite Character Models/Bug

Hello all, im new to SL. I recently instaleld the game and logged in, but it seems that all the player avaters are bright green/yellow/purple depending on how far in or out i am zoomed, only at a specific distance can i see the clothes at their proper texture and colours, all other times the characters are just one block of this colour. Any ideas on what this is and how to solve it?

I'm downloading again soon and reinstalling, thats all i could think of.

Thanks in Advance.

im lazy , but im guessing you have vertex corruption.

Thanks for the clear instructions, it doesnt seem to have had any effect though unfortunately.

Know what vid card you have?, might be driver issue next up on checklist.

ati - omegadrivers.com
nvidia - um... nvidia.com

anything else youre in bad luck