Thanks to all of you.
Well, I did try the suggestion and unchecked the use hardware acceleration and the problem vanished and i had whole face once more, but did get some strange color results on other models I'm working on.
when playing around with uncheck accelerator I also got a warning that SU detected I am using 16 bit window displays and should change settings to true color (32 bit).... sorry but, I'm a bit computer challenged how does one do this :O)
I think I have have an Intel card, again not sure how to find this out, but if i right click on my desktop and go to graphic options an intel sign comes up, which I haven not messed with... for obvious reasons :O)
the sketchup hardware requirements says
2+ GHz processor.
2+ GB RAM.
500 MB of available hard-disk space.
3D class Video Card with 512+ MB of memory or higher. Please ensure that the video card driver supports OpenGL version 1.5 or higher and up to date.
SketchUp's performance relies heavily the graphics card driver and it's ability to support OpenGL 1.5 or higher. Historically, people have seen problems with ATI Radeon cards and Intel based cards with SketchUp. We don't recommend using these graphics cards with SketchUp at this time.
So I guess i have to get a new vid card.....meantime can anyone explain how I change my setting to true color 32 bit.... Thanks