cannot empty trash

I'm trying to free up space on my computer. Took me a long time to go through all my files and delete unwanted files. Now I'm trying to empty the trash and it says I have locked files in the trash. But when I give the computer the "consent" to securely trash everything it doesn't do it.

I'm getting so frustrated with Macbook air 2012. Am I the only one who is having so much problem with apple products?

Please help.

Thanks