If you connect the camera to the computer via USB and select the 'Mass Storage' mode on the camera, you will see the camera's memory like a USB stick on the computer and can copy and of course delete the files.
Directly on the camera, in playback mode, there is probably the possibility to delete an image or a shot by pressing the (?) release button for 1 to 3 seconds. (Not sure if I had read that on this model).

First of all, go to the video or photo you want to delete. If you press the power button once, you can change the mode. Now switch to the fourth mode where you can change your settings. Now you only have to click down (with the lower side button) until you come to a point where it says delete. If you now go to this point and confirm with the OK button, a message will appear saying "Do you really want to delete this video". And now you just have to click on confirm and confirm it with the OK button. This way you can delete the videos and photos. Unfortunately, you can't do this with the computer. I know this because I had the problem myself some time ago and I simply tested everything until I came to this possibility.

Format memory card?