I can't open the current Photoshop v27.5 on my PC (for the first time ever). I deleted the old version and re-installed the current one. The startup illustration flashes on the screen for a second and then disappears and then nothing happens.

Hi!

Do you mean that this is the first time you are logging in to that version on you PC, or the first time you have not been able to log in with v27.5?

Have you checked that your hardware and your Graphics Processor card are compatible with the latest version? 

Here is a help doc that gives you the specific hardware requirements to run v27 on your machine: https://helpx.adobe.com/photoshop/desktop/get-started/technical-requirements-installation/adobe-photoshop-on-desktop-technical-requirements.html

Please take a look and see if you meet these— and let us know if you still need help?

Michelle