1) I've been checking this issue on other sites and different people are being told different things by VCom. Some are told no update is planned, some are told an update is in the works with no completion estimate, and some are told it's a Microsoft problem and VCom is waiting for Microsoft to issue a fix.
2) I see that Avanquest's website now says specifically that PDP 9 is Win 10 compatible. That's in the Buy Now ad, and it was added within the past few days.
3) Most of my PDP copies are 8.5 and there is no mention of an update for 8.5.
4) There is no trial download version of PDP9.
5) I haven't re-tried either 8.5 or 9 under Win 10. So I don't know if the new compatibility is because VCom has done an update or Microsoft did fix the problem.
6) I figured that if there is a new fixed version of PDP9, that it might be available from within PDP9 as an update. Running PDP9 under Win 7, I ran Check for Updates and got a message that I have the latest version and there are no updates available.
7) Regarding on-line versions of 7 having malware, I did find a download from Avanquest's FTP site with a promo with free product key from Avanquest available by email. I'm not going to give the URL here, but if you search diligently for "PowerDesk Pro 7" and UK you can find it. (I don't remember whether the double-quotes are needed.) Unfortunately, I don't remember where I found the link. Remember -- the download link has to be to Avanquest's FTP site and was offered through Avanquest UK. It's not a third-party "hot deals" or similar site. (What I have found over the years is that some companies offer "limited time" upgrade/discount/promo prices and later they remove the links from other pages on their site but they don't remove the actual page. If you can access the page directly, e.g., by hitting the proper search terms on a search engine, the page still works as to adding the item to the shopping cart, etc., completing the transaction, sending a working download link, etc. That seems to be the case with this promo.)