|Possibly one or more bad RAM modules which is corrupting data during transfer, so I would start by testing the RAM using a bootable CD with the Memtest86 utility on it.|
Download Memtest86 pre-built CD ISO file from here: http://www.memtest.org/
Now download IMGBurn from here & install it: http://filehippo.com/download_imgburn/
Use IMGBurn to burn the Memtest86 ISO file to a blank CD-R.
Now boot your LifeBook from that CD to start the Memtest program.
Usage instructions can be found on the site you downloaded Memtest86 from.