DJDP,
It appears that you have a memory issue. You should run the DOS memory tests to remove the OS and drivers from the equation. You may download the DOS boot disk from the Lenovo site.
Walking One Left Test: The Walking One Left Test starts by setting all bits in a byte to a value of zero. One at a time from right to left, each bit is set to a value of one and back to zero. The test then reads each bit value in the byte. If the bit values in the byte are inconsistent, the test logs as Failed. The test loops from low address to high address for all available pages.
Walking One Right Test: The Walking One Right Test starts by setting all bits in a byte to a value of zero. One at a time from left to right, each bit is set to a value of one and back to zero. The test then reads each bit value in the byte. If the bit values in the byte are inconsistent, the test logs as Failed. The test loops from low address to high address for all available pages.
-Fred