You should be able to still download the free 3.11 software, as was mentioned. However, have you called PlasmaCAM directly to discuss this? I would assume that they could de-activate the seat that is in your old (not working) computer and free you up to run that seat on a new computer.
When I bought my DHC2 used, I called PCam and they gave me a form to have ownership changed - which updated their records, and allowed me access to their online support community. Judging by your post, it doesn't sound like you have obtained access to the online support forum (which is also where you download software and order parts). You might want to look into that.
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