Was clearing out a load of crap off my HD and managed to get rid of what it said was over 1gig of Car videos (i still have about 7gig of em on there

).
Turned PC off about 30mins later.
Turned it on later and suddenly it says i got at least 700meg less than before
Usually when turn on a PC it says more HD room than last time it was on, not less
Wheres the space gone?