BTW, if you are going to try Hachman, don't get the latest 8.x release on the homepage. It introduces a low file size limit in the freeware version, making it unusable for editing the data.000 file. It is still possible to find the previous 7.x release, though; check here, or search Google for "hack704.zip" or "hack702.zip", etc.
Alternately, there are other the freeware programs, such as Frhed, XVI32 or those listed here or reviewed on this site.