hi Folks, thanks for all the tips! My case is finally resolved, and I found the root cause of the 'low memory' error message, file is in use error, slowness of the program, and various program crashes, due to the project file have TONS of slide masters within it. When working with the support team, he mentioned about having the file in a 'new file'. This triggered something for me, as in the case with both of my project files that were giving me troubles, they had both been old presenter files that had been imported to SL2 and then SL3, and now SL360 - well all those slide masters came with it. I had applied a 'bIank'/clean slide master to all the slides, but those masters still remain even though they aren't used.
I eventually ended up having to copy in just text, images and audio into a brand new SL360 file so no slide master layouts came in - once I did this, no issues of the low memory error, file is in use error, or program crashes or slowness. I tried to delete the slide masters from my original working file, but it would just crash on me so given my tight deadline, I couldn't waste anymore time and just found it faster to copy and paste what I needed into a new file...... even though these projects are both approx. 200 slides (+/-). I had multiple copies of both my project files from doing 'save as' because I would get the 'file in use' message. I lost hours of work and changes because I never knew if my file would save.
I had gone to my IT support and had them install more RAM on my computer and was working off my C: drive - I had turned off the auto-save feature to stop SL from creating tons of huge zip files. Articulate support had provided some uninstall/reinstall steps, I had just installed 360 so didn't feel that was necessary and/or part of the issue.
So it took me some investigating but finally determined it was those darn slide masters!!! There were hundreds of slide master layouts - it was unbelievable!!
So, my advice if you run into this issue, check your file for slide masters!!!!!! and/or start with a new file. I hope this can help others who run into this issue!!