i can't seem to find out what's causing this loss in hdd space. sys restore is off. It's like this a month or so n' i've run out of ideas what to try, anyone?

Bioshock rootkit?

Quote from spankmeyer :

Bioshock rootkit?

nope, dont own that one

Quote from CSU1 :

i can't seem to find out what's causing this loss in hdd space. sys restore is off. It's like this a month or so n' i've run out of ideas what to try, anyone?

A good proportion of that will simply be the MFT 'overhead' for the NTFS format, which is usually somewhere between 12 and 15%. Potentially more of the space is taken up by indexing (if you have indexing enabled on your drive).

It's not unusual to "lose" that amount of space off of an NTFS drive.