Why doesn't my file open after i use photoshop brushes,it was saved on Photoshop as a PSD file?

i have a pc n I was using the brushes i've downloaded from online. And after i saved the file and closed photoshop, i went back to the file to open it but it wouldn't open; kept on saying ''Could not complere your request because it is not the right kind of doent." But it was saved as a PSD file.