Msconfig maximum memory issue

I am now using Windows 8.1 (and will post something on the Win-8 Forum) on an old Dell XPS 600 desktop PC. But this Win-7 thread on maximum memory settings really saved me; THANKS. Lessons learned:

• First off, there is probably NO legitimate way to increase RAM capacity of most old computers.
  
  
• Second, never fiddle with the Maximum Memory settings in Msconfig.exe (“System Configuration;” “Boot” tab; “Advanced options”). No matter the temptation, leave the "Maximum Memory" box unchecked.
  
  
• And for the love of God whatever you do, do NOT re-boot the computer with the Maximum Memory box checked and maximum memory set (e.g., by Windows) at zero. (Very BAD!)
  
  
• Regardless of the Windows version, it seems like corrective options provided at boot-up almost never help with YOUR particular problem.
  
  
• So if you find yourself in the quandary where your computer won’t boot after you inadvertently changed memory settings in Msconfig, use instructions in the recommended tutorial (Memory - Set Maximum Amount Used by Windows) to manually reset the maximum memory (using Command Prompt commands) to some reasonable number greater than zero.
  
  
• Then without re-booting start-up Windows from the Command Prompt if you can (e.g., using Winint.exe). (Re-booting did not work for me.)
  
  
• If you manage to get Windows back up and running, re-enter Msconfig a final time, make sure the maximum memory box is unchecked (the way it is supposed to be in order to use maximum available memory), save, and re-boot. Then, as someone said, do not ever touch these settings again if you know what’s good for you.

(Whew! My next step was going to be to re-install Windows. Thanks, people.)