Windows 7 System monopolises hard drive when procesing video files???? HELP

when trying to process recorded tv files into dvd files using nero the hard drive read/write is huge and the process monitor shows the 'system' file is monopolising the hard drive. i disabled superfetch and that stopped it at the time but it now keeps happening and i can't see whats causing it. any ideas?

If you recorded the files as uncompressed video, this is perfectly normal.