This really is HR Block's issue, notwithstanding that its tech support is stymied. Perhaps you could call back and ask to have the issue escalated.
What do you mean by you "ran Runtime Library reinstall"? Where did you get the runtime library to reinstall?
I have 9 different instances of msvcr90.dll on my XP Pro system, each installed by a different application. The interesting thing is that they are not all identical. Most are version 9.0.21022.8, but I also have 2 instances of versions 9.0.30729.1.
Applications that use Visual C++ are supposed to include the runtime library with their distributable package. Usually, the runtime library is installed in a subdirectory of the application's directory in C:\Program Files. For example, I have C:\Program Files\TurboTax\Deluxe 2010\32bit\msvcr90.dll
However, if some other application you installed placed a different version of msvcr90 in one of the system directories, e.g., C:\Windows\system32, it's possible that the HRBlock executable is attempting to use the wrong file.
I'd do a search of your hard drive for msvcr90.dll and see if there is an instance in a directory other than one clearly associated with an application.