Well, you'd still need to use an OS, but not the one installed on your hard drive. All you need is a free Live CD version of a Linux distro, such as Knoppix or Ubuntu. With a Live CD you run the Linux operating system directly off the CD, no installation necessary, leaving your hard drive out of the loop. You can then go online (provided the OS supports your modem) and browse your hard drive to recover (copy files to another hard drive) your data. Once the problem's resolved, simply remove the Live CD and return to your original setup.
Hope this helps,
I have been pondering something for a very long time. I wonder...... If your computer gets hacked, hi-jacked, virus infected, becomes inoperable, etc. Is there a way to boot from a cd-rom and gain access to your internet connection? I have a dial-up connection. Suppose you need on-line help and only have one PC. Can you get access to the Internet without running the OS? I know it sounds far-fetched. But, I had to ask. I ask to learn and learn to advance.