Once I entered to the world of high scalable computing it became common to handle file larger than 2 Gb. Usually files are more than the amount of ram a computer has. for e.g the English Wikipedia dump is around 9 Gb with 3,500,000 articles. The whole Wikipedia seems to be around 29 Gb. The whole file could not be open in common windows editors like notepad or NotePad++.
LTFViewer is a decent option in windows to open very large files and probably it loads one page at a time into memory.
I went back to VI editor in Linux .Here goes some useful commands.
To switch from Insert Mode to Command Mode, press the Escape (Esc) key.
Let me know via comment or email if you know any other software in windows which can open very huge text files.