That user is saying to reinstate your page file if you had removed it, earlier. I doubt you removed your page file—it would cause other programs to get out-of-memory errors—so probably nothing relevant in their message.
The first thing to change about your system is to use 64-bit Windows 7 (or 8). The 32-bit OS you have on there, now, is limiting per-program memory to less than 2GB (1651 MB seems to be what PS can use), despite having four 4GB total, so until you update to a 64-bit version of Windows you cannot use more memory even if you added more memory.
I can’t quite read everything in your system configuration, but you probably need a new motherboard and an i7 processor, or an AMD equivalent.
Obviously the other thing to do, after running a 64-bit OS on a motherboard that supports a 64-bit OS, is to add more memory: 8, 12, 16GB would be much better.