How do I delete pictures from my memory card.. the camera says card is full?

Brenda, Although I only have a little to go on, I'll give it a try.
(only brand, not model)
Olympus camera's do have an internal memory, but just for a limited amount of pictures. When your camera says Memory full, this internal memory is full. You can place a memory card, or free memory, by deleting pictures. But don't delete a picture before you are sure you saved the picture on the computer or some other media.
If you want a memory card, check what type of card goes into your camera. When you place a memory card in the camera it has to be formatted (check the manual) but NEVER format a memory card, when you have any pictures in the internal memory, because you could loose all the pictures in the internal memory too.

Format the card again.

The memory card should be formatted each time you finish transferring your pictures to your computer, in order to avoid exactly this type of situation.

Internal memory means the memory of the camera. Deleting the pictures in memory card will not solve the problem.
In the menu you will find a menu item as storage (or somewhat similar). Set this to internal memory. Then delete the pictures (or better, move all the pictures to memory card).
The above steps will correct the problem.

Your camera is talking about its internal memory. If you want the card to start working, you must get rid of the pics on the internal memory. With no card in the camera, go into the menu and find "format" and follow the on-screen instructions.

Deleting pictures one by one is time consuming and hard on the memory card. Right now you have deleted the images but the memory card needs to be formatted. Always format the memory card never delete what camera make and model are you using and do you have the manual?

Take out memory card from camera, format internal memory to delete all pictures at once or delete them one by one.
Once memory card is inserted in camera, internal memory is no longer available to store/ delete pictures so remove memory card from camera to get access to internal memory.

Suggestion is to format the memory card and permanently delete all of the images from it. The card should then be able to be reused and you can start taking images again. To format the card go to Menu - setup and press ok - go to format and press ok - go to yes and press Ok. This will clear the card and you are back in business.

Try going to settings of your camera while memory card is in and instead of deleting try and look for the option to format your card. And that should be it.

If memory card is full, just try to delete one picture and try to take a picture and check if it will be saved in the memory card.

There is a Delete All option.

Or if you want to, you may format the memory card and the pictures will be deleted.

It's quite possible that it's actually taking photos and storing them to the camera's onboard memory and not the memory card, explaining why it gets full so quickly with two pictures and why you can only delete two pictures. Look for a setting to change the storage to the memory card.