The Windows version is already pre-compiled into an EXE and is ready to rock out of the box...
The instructions to "install msys/mingw" are to compile the exe yourself from the source code.
Long story short, just open a command prompt and do a "CD" to the folder you extracted it to (that contains the EXE file) and run the file with the desired arguments.
Here is a better guide on How to use the Windows GPU Plotter:
1) The GPU Plotter is archived in a .7z file, so you will need to Download and install 7-zip to be able to extract it (if you don't already have it):
http://www.7-zip.org/download.html2) Download the (Windows) GPU plot generator v2.0.0:
https://mega.co.nz/#!2BNDXY4L!jgwHDZXDJyFp2Jg5mN8sxtpplgXEInSMf1cQGbPc5lM
3) Right-click & extract the "gpuPlotGenerator-bin-win-x86-2.0.0.7z" file and select 7-zip -> extract to "gpuPlotGenerator-bin-win-x86-2.0.0\"
4) open the newly created "gpuPlotGenerator-bin-win-x86-2.0.0" folder
5) In an empty space within the "gpuPlotGenerator-bin-win-x86-2.0.0" folder do the following:
Hold down the "shift" key and right-click in an empty spot. Select "Open command window here"
(Note: the "Open command window here" option is only available if you hold Shift and Right-Click)
(Alternatively, you could just open a command window manually and do a "CD" to the folder containing the gpuPlotGenerator.exe file)
6) find the GPU's Platform and Platform ID:
gpuPlotGenerator.exe list platforms
(Note down the "ID" number for the proper device platform, this will be <platformId>)
7) Find the DeviceID of the device to use:
gpuPlotGenerator.exe list devices <platformId>
(Note down the "ID" number for the proper device to use, this will be <deviceId>)

Type the desired plot information:
gpuPlotGenerator.exe generate <platformId> <deviceId> "<Plot folder path>" <AccountNumber> <StartingPlot> <NumberOfPlots> <Stagger> <Threads> <Hashes>
As an example, this is the command that I used on my AMD Radeon 7800:
gpuPlotGenerator.exe generate 0 0 "C:\Plots" 11111222223333344444 14670000 7335000 1000 64 1024
These directions are better than nothing, but I still start to lose it on step 6. Where the hell am I supposed to find these ID numbers and why can't the damn program find them on its own? And in the above example, it seems that a pair of zeroes are used for these purposes? WTF?
And as shown in step 8 - go into more detail about how and why each character, symbol, and space was typed. Define what each group of numbers is and what I'd want to write there for use on a 7950 270X 280X. I need pictures and words and arrows! To install it on 7 64 bit.