Peg, Welcome aboard.
Do you have any other trouble with your computer. Since this file is from the operating system and not the game, if this file is the cause of the malfunction you should have some problems elsewhere.
You might check with Microsoft to see if you can reinstall the Microsoft Visual C Runtime library version 7.1 engine, or at least get the file from them to replace the msvcr71.dll file. I think there is a site on the net where you can get some of the .dll files, but I am not sure.
You state you replaced the file. Where did you get the replacement?
SEE:
http://www.subsim.com/radioroom/show...ht=msvcr71.dll