If the shutter blades are stuck, you will need to clean the mechanism.
Most of the time, a simple "flood-cleaning" with Lighter fluid or 99%pure Isopropyl alchohol will get them moving again. Repeated applications might be necessary. You'll know if the blades move when it is wet, but stop after it dries out.
You will need to remove the front lens group to do this. I used needle-nose pliers to take off the retaining ring. The name plate comes off. Then use a rubber cork to remove the lens group. That leaves the blades exposed, ready to be cleaned.
If you are handy with mechanical repair, this is not hard. If not, you might want to look for a repair shop.