Using solidworks 2010 (because we only have 2010 in the university)

1 - How do I make one part doesn't have back-force to the first parts. Like in attachment 1 - Mechenic.png, How do I make endless screw can control the sliding component but the sliding component not be able to drag by mouse?

2 - A chain like this(Mechenic_02.png)how do I make the next segment do not affect the parent segment? (a large assembly with many flexible parts always encounter movement error if the movements are not decoupled)

3 - When I trying limit distance and angle at the same time (like an X structure), I always get error "overdefine" and infact the parts can still be moved and not fully defined yet when I try to limit another parameter, it always says "overdefine".

Many thanks.