screen turns green and pc locks
 

i have k lite mega i saw a movie other day ran fine now it plays 10 seconds then screen turns green w sound i read w the dots why would it play and cut out
properties of video doesnt say how its coded is it corupt
also when plays mouse freezes a bit pc locks

I would say:
(1) Uninstall mega-pack (see this post why.)
(2) Register and download latest BSPlayer from the original site
(3) Install BSPlayer
(4) For starters install DivX-codec and perhaps XviD
See this post and/or this post.
For further codecs needed use adicoto's list of codecs as also mentioned in the earlier posts referred to hereabove.