Hard Drive Space

[EVOEvo]

when i use dvd shrink to make a moive i had 5.74 GB so i did Next friday then burn it then i went to make another moive Jurassic park so when i started backing it up said there files alrdy there del yes or no i hit yes then it started backing the moive up. then i got a error out of disk space im like WTF i just had 5.7 gigs now it shows me to only have 2.64 gigs and i cant figer out were its going. its been doing this awhile i just not caught on to it but i was thinking something was happening to my disk space. dose any body know a cure to this or could it be a virus cause i been getting that stupid mblaster virus like ever day it pops up said virus removed but still it comes back on there. and my mblast remover wont even find it no more. im about to reformatt c: as bad as i h8 to just did it not to long ago and hope it fixes the problem.