Freeing up disk space

My disk is getting near to full. Whenever I delete files it seems to have no effect on the space left and I have just done a Norton "clean" and the free space has actually reduced. I have googled to find help and I have emptied my trash but to no avail.

To be frank I find the other suggestions too technical to make sense to me.

Has anyone got a brilliant idea?

Google should be able to help you, not this forum.