If a binary file is opening up as if it were a text page, then it's not a browser issue, it's the webserver that's misconfigured. The server is sending out the file with the wrong mime-type, and so your browser thinks it's actually a text file. It's possible to use certain browser extensions or proxy filters to change the mime-type to match the file extension, but that only works on an individual level, and it can cause other headaches in the meantime. You really need to contact the hosting administrator and have them correct it there.
The top command can show you the current memory situation, in addition to the processes that are currently active.
Finally, yes, you almost certainly need to download and install the 64bit operating system separately. I don't remember ever seeing any installer, or even live cd for that matter, that has both options available. Not that I've been looking, however.