Don't confuse the updaters (1.41 and 1.5 update BF2) with the patch ( PR v8.6 to PRv8.7 update the PR mod) Use the full installers linked below.
Installation timeline
1. Install BF2
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BF2:SF Expansion | --- If you have BF2:SF, here is where it should be installed.
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2. Install Battlefield 2 v1.41
3. Install Battlefield 2 v1.5
4. Install the latest PR Build (Currently: v0.874)
BF2 not updated to v 1.41 before updating with v1.5
FULL update 1.41
Final v1.5
Some have posted Updating with the
1.5 update
Sometimes does not complete, but looks like it does.
To find your version of BF2
run PR in 'windowed' mode
Look at the upper left corner
you should see
v.1.5.3153-802.0
Incomplete install of 'Core' & 'Levels'
Project Reality v 0.87 uses TWO separate Client Installers and should be installed in this order.
Core first and followed by
Levels.
(Use the 'levels' installer to make a desktop short cut.)
If you get any errors, download a new installer from a different source and try again.
Compatibility mode to xp and run as admin not set in desktop shortcut on Vista PCs
Right click shortcut
choose 'properties' from bottom of list
Click on the Compatibility 'tab'(along the top of the window)
Check 'run as admin' box, select WINDOWS XP(service pack 2
Project Reality v0.87 Installation Guide
Good luck