onigiri1998

Hi, I have an unmodded version of the beta i tried to get one one day and saw it had uninstalled from my steam library, further inspection showed that steam had stopped recognising my steamlibrary in my D: drive and 3 other games had been uninstalled. I opened the game directly from the exe file and it played fine. I deleted that version of Arma and reinstalled on steam. i came in and tried to open a custom mission I had downloaded. when I tried to open it it came up with the message cannot play/edit this mission dowloadable content missing. I read up on this and found this had been a previos problem with the ifrit classchange. It was not just the Ifrit which was missing (im not at my own computer i will check soon but i am sure the KA-80 was one of them) is this another classchange mess up or is it a more serious problem?? I have started to reinstall ARMA agian but not sure if it will work. Edit: Re-installing did not work