Advice on software notes to tone generator

I need to clarify my request beyond a simple title. I enjoy singing in a chorus but I struggle up until performance day because I do not read music. I listen to my other tenors and the accompanist and memorize my part by ear. That said I would love to have a piece of software for my computer that has all notes in notation and I can consult my sheet music then locate it on the screen and play that note. If nothing more it will help me land or start on the proper note as I start. Especially useful for Key shifts which take me a while to grab and and not slide into as I start off the mark. I need to clean up my act so to speak.

Any suggestions? Thanks in advance for any assistance you all may offer. If I am in the wrong place to ask this let me know. JB