Back in Win3.x (if not earlier) there was the program called PaintBrush. Beginning in a later OS, it was renamed to MS Paint, however there was still a pbrush.exe stub program which launched mspaint. So typing pbrush at the command line would launch mspaint. (Same thing with Write, which was superceded by Wordpad.)

I never liked the redesigned UI in the Win7 version of mspaint. It's possible to run the Win2000 version, and so I was generally doing that. But, out of habit I also sometimes type pbrush at the command prompt to open a BMP. This launches the old Win2000 style mspaint. At first I didn't question it, then I finally realized... The Win2000 EXE is not in my path. How on earth does typing pbrush launch the old mspaint? Then I checked the WINDOWS directory and discovered there is a PBRUSH.EXE dated 2003. Apparently Win7 ships with both versions of mspaint.

Now comes the weirdest part. If I bring up the Run dialog with windows-key + R, and type pbrush, it launches the new-fangled version! Why is pbrush a different program launched from command line vs. Run dialog??

i don't have any pbrush on 7sp1

So I tried what you said in both classicshell and Metrotard in Win10 rtm 10240.

 

pbrush loads paint both times. Also thrice from the 'run' menu Win-r.

 

No old version anymore.

From a Windows 7 SP1 x86:

 

C:\Windows>dir write.exe /s Volume in drive C is LocalDisk Volume Serial Number is 00A6-4701 Directory of C:\Windows07/13/2009  09:14 PM             9,216 write.exe               1 File(s)          9,216 bytesC:\Windows>dir pbrush.exe /s Volume in drive C is LocalDisk Volume Serial Number is 00A6-4701File Not FoundC:\Windows>dir pbrush.exe /s -a:h Volume in drive C is LocalDisk Volume Serial Number is 00A6-4701File Not Found

Write.exe has the original Write icon but opens WordPad.

Running pbrush from cmd doesn't work, but running it from the Run box launches MSPaint.

C:\Windows>pbrush.exe'pbrush.exe' is not recognized as an internal or external command,operable program or batch file.C:\Windows>pbrush'pbrush' is not recognized as an internal or external command,operable program or batch file.