Ha, it's funny that you mention both of those programs Blender and Draftsight. I recently downloaded them because a guy from another EV site recommended Draftsight for drawings and I just came across Blender by searching. I haven't tried either yet because I wanted to go straight into 3D design. Blender looks like it's made for animating and I presently don't really have a need for that...it looks really cool though.
It's also funny that you mentioned and older PTC proram. I used a program called PRO Desktop Express from PTC quite a few years ago on an older computer and it ran fine. In fact, I liked the layout of the workspace way better than Creo. They had a free version back then...too bad it's not free anymore...
I checked the requirements to run Creo and my computer is all over it. I'm not going any further with it until I can resolve this problem. I'm sure it will come back...somehow!?
Cheerio,
John