Simulate stand alone

Hi all,

for work I use Creo 3 linked to windchill so, to open a file, I look for it always inside a workspace of the PDM. For our corporate rules, the only CAD files that we manage outside the PDM are the simulations, so I have different folders with many Creo files.
Yesterday I had to do cleaning of old files and, for mistake, I've done double click on  one. Usually I don't open a Creo file outside of windchill in this manner, anyway I was sure to start Creo Parametric; instead it started Creo Simulate like a stand alone program.
I knew that there was only the FEM mode like stand alone (I've never use it because we not have the licence) and now I don't have time to investigate the possibilities of the other Simulate stand alone.

So, at the end, my questions:
which are the differences between using Simulate within Creo Parametric and:
A) stand alone in FEM mode
B) stand alone not in FEM mode

Thanks
Bye