S3 Virge With Dual head stuck in virtual desktop

[Barry4k]

hi could somone please help me i have a s3 virge mx+ in an Nec computer and it has 2 monitor outs (i think its dual head). i am running win2000 professional and it wont go out of virtual desktop mode when im over 640x480 resolution. when i do get it out of virtual desktop its in 16 coloour or 256 colour mode... then as soon as i put it in 16 bit it goes back in virtual desktop also when i run 640x480 in 16 bit colour or higher the screen is split in 3
if anyone can help me please e-mail me barry199@dingoblue.net.au