So, when I first entered Markarth, apparently Weylin was supposed to attack Margret, but this never happened. They're both standing there in the market, day and night. I wanted to play the Forsworn Conspiracy quest, so I read a bit about it online and determined that the next step was (maybe??) to go to the Shrine of Talos in Markarth. But when I got there, a bunch of guards tried to arrest me, and a message flashed on the screen that I had completed the Forsworn Conspiracy quest...except I really hadn't.

WTF? Anybody know if there is a way that I can fix this. BTW, I'm playing on the PC.

Try reloading an earlier save and typing setstage MS01 10 into the console.

Thanks! I will try that.

I've already completed that whole quest, and if I go into the shrine again it's as if I haven't..

They want to kill me indefinitely or take me to prison... again... lulz