You're running DOS-with-knobs-on, which is still subject to the 64K apiece USER/GDI heap arseup, and on which your suspicions about "low memory" hold a little water (although not much; the low memory thing is to do with 16-bit applications; Firefox and its extensions are 32-bit).
If Windows annoys you so much (and I can see why it would), there [link|http://www.ubuntu.com|are] [link|http://www.apple.com|alternatives].