Since, as you say, you have tried the various solutions described on my site, then we might be left with guesswork.
Your feeling that it might have something to do with pasting into WP might be correct. "Trust your gut" is sometimes good advice since you might have noticed other contemporaneous factors when the problem surfaced that might be involved.
Does it happen when pasting the SAME material into a new, empty document or only when pasting that material into an existing document? The former could indicate a problem with the pasted material (or with the default template); the latter could indicate an issue with the target document(s).
Does it happen when pasting a small amount (a few paragraphs or a few pages) of PLAIN text from the current document or another document? If not, maybe the source material is corrupted. (Not only pasting images, but pasting with formatting, tables, etc., can be problematic.)
Inasmuch as you have the same problem with other computers, my guess is that it could be a WP setting -- such as the WP automatic backup being set for a too-short time interval. See under Option #1 at http://wptoolbox.com/tips/AutoBAK.html . Pasting into a document from another source can involve conversion activities (e.g., images), so there could be program activity that might not be finished when the next automatic backup period starts.
In effect, increased disk activity at the time the program freezes could indicate the program can't do something or can't find something.
Did you also try fixing the default template (and here I assume it's the one the program installed, not a copy of an older template)? It "spawns" new documents, and if it's damaged it can send the damage to the new document. It's easy to fix. For information on the default template and custom templates -- how to find, create, modify, or fix them, etc. -- see http://wptoolbox.com/tips/Templates.html
Also: Is your WPX7 up to date? Corel has Service Packs on their Support page: http://www.wordperfect.com/en/pages/800161.html