The MSVCR100.dll file is part of the Microsoft Visual C++, redistributables. You can install them and see if this solves your problem. After installing the above mentioned, check if your wamp installation is correctly setup.
For Windows 32: Be sure that you have installed the Visual C++ 2010 SP1 Redistributable Package x86: VC10 SP1 vcredist_x86.exe
For Windows 64: Be sure that you have installed the Visual C++ 2010 SP1 Redistributable Package x64: VC10 SP1 vcredist_x64.exe
Apache will not run without this component
In fact, if you are running the 64bit Windows it is a good idea to install all the 32bit libraries as well as the 64bit ones. After all 64bit windows run 64 and 32-bit code. You will probably find you need at least one of the 32bit runtimes for some app/utility you will install at some point.