Ruby scripts error on windows 7

Hi brothers,
I am trying to run some scripts that are programmed in ruby on rails programming language.
They were working just fine in my previous operating system i. e. Windows XP, so there is not issue in them.
Now I upgraded my windows to windows 7. After that I am unable to run these scripts.
Whenever I clicked on the file, I got the below mentioned error.

Rubyw.exe – System Error
The program can’t start because MSVCR71.dll is missing from your computer.
Try reinstalling the program to fix this problem.
I tried reinstallation of ruby on my windows pc, but still unable to get the ruby files running on it.
My computer is Pentium IV 3.4 GHz with 2 ram and 300 hard disk.
Thanks.
