Help PR.exe error

[nocs2]

pr start but I quit a warning :
YOU MUST RUN PR BY RUNNING PR.EXE NOT BF2
PLEASE PRESS ALT+F4 AND UPDATE YOUR SHORTCUTS!
PR.EXE IS NEEDED FOR OUR COSTOM SHADER EFFECT TO WORK
IT WILL PASS ANY SUPPLIED PARAMETERS ON BF2.EXE
HELP MEEEEEEEEEEEEEEEEEEEEEEE

[thepalerider]

Search + PR.exe error = 36 posts with answers a plenty.

Oh and by the way if you read the red "stickys"
at the TOP of PR Help and Hardware Issues
You will find the answers to the most commonly asked questions.

As a matter of fact the first one:
"Solution for launch problem: "bf2.exe does not exist"
besides being(cough cough)
brilliantly written, should prove to be helpful to your problem.

DEADFAST has written a great guide as well:

Troubleshooting guide: Unable to start PR

Hope it helps