Indeed: Pentium 75 is P54C and from 1995, while PAE (Address Extension to get beyond 4GB) was only introduced in the Pentium Pro (P6) series in 1995.
Yeah, 16MB. Orders of magnitude get lost easily when talking about computer technology. Hell, the computer I owned before that (A Commodore 64) had 64KB of memory and that was a lot when it came out. And now 16GB is probably the most common memory size you see on PCs in the wild.
Speaking of memory, I think yours is failing! Ain't no way!