If your machine has been working correctly and you have not made any changes to it then there is a chance that a corrupt .xml file is causing the current problem.
There is a Mach3 sub folder ‘xmlbackups’ – try choosing an earlier backup (preferably before the problem started), rename it with the .xml extension and copy this to your Mach3 folder. Restart Mach3.
If this does not cure the problem then perhaps ask you question on the Warp9 forum
http://www.warp9td.com/index.php/kunena/index where I am sure they will have more suggestions for you to try.
Tweakie.
n.b. I have removed your other post as duplication of same topic postings just diversifies response and is not helpful.