some more details:
- same footage watched directly from tape (when camera are attached via analog output to the TV) do not shows any 'noise' - thats mean that picture on tape is clear, but noise comes during the capturing process
- as computer is quite new , there from 160 GB are still not ocypied up to 110 GB , thats mean that also 'defragmention' there is not a case

what I'm worried and may be somebody has an experience - since the hardware solutiuon is quit new (Intel 915PBL MB+Intel P 4 3,2) and fast, there may be some impact from that that MB is too fast or some role is playing software installed and running in background (as I said ,there were running Symantec systemworks which has active Norton undelete feature, antiviruss and firewall which also has some impact on processor interrupts). Any expierence with playing with such software are welcome ? Is this really mean that such problem drops only to me ?