[Cube] video riser?

[gladys pérez-almiroty]

hi:
my cube 450 mgz,  1.25 gb ram and 120 hd has been showing problems.  
it boots, but then turns itself off at different lengths of time. a  
while back i was told to check  and see if the video card was lose.   
i am having eye problems, insert long, sad story here- and today  
finally i was able to open the cube.

i  am broken hearted: a green plastic part fell off. i  believe it is  
the connector on the video riser card. i was looking at the service  
manual, but have been unable to find a better way to explain what it  
is. in the service manual, on  page 40,  second illustration, the  
plastic cover that surrounds the video riser card looks brown. mine  
is green.

my question is this: besides the video riser card, should i look into  
something else, considering what happened?
thanks for all and any help,
gladys