Soldat will only work for me the first time i start it up. The next time i play it will freeze up and give me a blank purple screen right after i start a map. The only way i can keep playing is if i Re-install the game EVERY time i want to play.

specs are P4 1.8 GHZ, 1024 RAM, GeForce FX 5200

Can anyone help?

Try reinstalling your video-card drivers, if that doesn't work, then downgrade to an older set of video-card drivers.

UPDATE your antivirus and run them. If it does not find anything check with other antivirus.
Run adaware and spybot updated aswell.