To protect your computer, and your network, any security expert with any experience will tell you to use a layered security strategy. One layer of security is to only run programs that you can trust, and to only access web sites that have trustable content.
Occasionally, you may need to run a program that you don't trust, or access a web site that has untrustable content. For many years, anti virus and similar security programs have used replicas of the operating system, called sandboxes, to do just that. When you open a file, run a program, or surf a web site from inside a sandbox, any changes produced by what you're doing go into the sandbox, not out into the computer operating system. When you finish what you're doing, you flush the sandbox, and any possible malware (along with any other results) gets flushed.
You can, just as easily, use a sandbox to run two parallel processes, like using your browser. If you want to upgrade your blog, and simultaneously examine changes as if you weren't logged in, you can run your browser inside a sandbox. You can be logged in to Blogger (Google) from outside the sandbox with one account, and logged in to Blogger (Google) from inside the sandbox with another account (or not logged in at all), simultaneously. Schizophrenia from a shortcut.
SandBoxIE was originally written to protect your computer while you run Internet Explorer V6 and earlier. You can, just as easily, run any other version of Internet Explorer, or any other browser, or any other program in general. Every file change that you make inside the sandbox gets saved to a replica copy of your disk, in the sandbox. Before you flush the sandbox, if you need to save anything specific, you can move it into disk storage in general. Then you flush the sandbox, and anything that you don't, explicitly, save gets flushed too.
SandBoxIE runs on your computer as a background process, and uses less than 4M of memory by itself, similar to the amount of memory used by 2 files opened in Notepad. Any processes like the browser, that you run from within SandBoxIE, use their normal amount of memory additional to that amount.
If your computer has enough resources, you can even use it to run multiple browsers on your computer, for transferring control of your blog(s) from one account to another, or instead of clearing browser cache.
SandBoxIE is free (on a trial basis), and easy to install. If you had started downloading it when you opened this post, you could have it running by now, and you could be using it.
Try it. I bet you'll find it useful.