Safe mode is what you need to use so an error can be generated. That error will help solve the issue.
Open your bf2hub client and click the launcher tab. Put a check in Safe Mode/ Window Mode.
In Width box type in 800. In Height box type in 600.
Click Yellow Play Battlefield 2 button on bf2hub client.
Load a singleplay map until it crashes.
Tell us the error it generates.

The one thing that would make it crash is if you cancelled the directx 9 install. Directx 9 is needed even with newer directx 10-11-12.
You can find the install for it (directx 9) from setup folder and it's named redist. Inside that folder is directx folder. Go inside it and doubleclick DXSETUP.exe.

FYI: He is using his own keys, from his own dvd's Prowler77

Thanks, I'll try all of this.

At the moment I have managed to play on cooperative servers, only two, "EFA Virtual" and "Digger's Den", but I still cannot play single-player games or multiplayer conquest.

It's a start

It's the crash report, we need, when the game is ran in safe mode @800x600 resolution.
Loading single play maps is all that's needed, if it crashes on those.
The error report is only generated, when in safe mode and not always guaranteed to generate one either.
If you get no error, let us know and we'll have you look into event viewer instead, to hopefully find the cause.

Thing i find weird is that you cant even play single player games. as far as i know those are pure local created server games by the program. Have you tried installing it on another machine?
Anyway i think your in good hands with Sharky and StandOn. I bet they will track down the issue.

A couple other things to try and rule out as an issue.
I'm not sure how you launch your game, using bf2hub client, or the desktop shortcuts.
Try what you haven't been using.
If you have been launching game with the launcher, try launching game using shortcuts, or vice versa.
Second possibility, try right clicking a desktop shortcut and choose run as admin, to see if that makes it load properly.

It really sounds like the levels are corrupt or something too. Being you can load a couple maps without issue.
If you used the install from this site, you can overwrite your levels folder from it.
open the zip, go into mods folder from it, then bf2 folder.
Now open your game folder (Usually C:\Program Files (x86)\EA Games\Battlefield 2)
Keep progressing into folders mods/bf2.
Drag the levels folder, from the zip and drop into this folder.
(Or you can just open the zip and drag the mods folder into C:\Program Files (x86)\EA Games\Battlefield 2 and overwrite the one in it. This will put all bf2 maps and special forces maps too)
overwrite all and if asked for permission, yes

Hello, it doesn't give me any crash report when loading single play maps, it just loads the map and when it's about to finish, it goes to the desktop.

I have already tried running as administrator, running in widows XP service pack 1, 2, 3 compatibility mode and with all the possible combinations between them ; )

If overwriting your levels didn't work.

Run event viewer. On the left side, click the arrow, next to Windows logs, to expand it. Highlight Application and scroll, on right side, looking for anything pertaining to bf2.exe.
Highlight System listing, on left too. Look for anything on the right, pertaining to bf2.exe
Most crashing errors will be in red with exclamation point. The yellow warnings are irrelevant usually.
You can right click each, on the left and clear them too.
Once cleared, open the game and make it crash.
Instantly open event viewer again and scroll for an error.
Less logs to look through this way.

Profile issue? Are you trying to load single and multi with the same player? Try making just an offline/singleplay account and try loading singleplay maps
If they load and work, try deleting profile folder and retrieve your account again, so it's synced correctly.
If it made no difference, just delete that created offline/singleplay account.

Read above again. You posted a response before I was done editing it.

I don't get any errors in the Windows event viewer, or when loading a single player game.

I tried deleting the profile folder and starting an offline single-player game and nothing, it keeps doing the same thing.

everything seems fine, but it won't start