Greetings, I'm teaching a computer hardware course at a community college and I have a bunch of old 486 VESA system boards that my students are learning on. I have the same problem with a number of these boards, and so far have not been able to determine the cause. The problem is as follows: When we boot up DOS 6.22 and the Himem.sys driver is loaded in Config.sys we get the message: "ERROR: Unable to control A20 line XMS driver not loaded". Anyone familiar with this problem? Thanks in advance for any advice. -Rick VanHeyst Do you want to signoff PCBUILD or just change to Digest mode - visit our web site: http://nospin.com/pc/pcbuild.html