Windscreen wiper not working?

I have a 95 Ford Fiesta, which is on it's last legs!
I haven't had a problem with the wipers until today. The drivers side wiper started sticking and became caught under the passenger side wiper. A piece of plastic came off the passenger side but it still works. I put them back to the parked position and tried again, the passenger worked but the drivers moved a centimetre and moved back to where it was.
If I pull the wiper up off the screen then it will move as normal, but it's when I put it back onto the screen that it stops. I think it might be the blade that is too close to the screen but how would I fix this?

Pull up the plastic cover above the spindle, there will be a nut there that may need tightening.
Most cars have these.

You think the blade is to close to the windshield? How would it wipe the water off if it wasn't touching it? With thinking like you have you'll never be able to figure it out, take it to someone before it rains.

Sounds like the nut holding the arm tight has loosened, not a big job, all you need is the correct size of spanner. All you need to do is line the wiper arm up where it should be when the wipers are off, lift up the plastic cover at the base of the wiper arm and tighten the nut.