2 days ago, I purchased and downloaded Adobe Photoshop Lightroom 6 and when I try to open it, it tells me that Lightroom has stopped working. If I can't get this to work, then I have made an expensive mistake. Help is greatly appreciated.
Windows or Mac? Are you seeing this error message while going into the develop module? If that is the case, try go to Lightroom's user preference dialog and under the "Performane" tab, uncheck to disable the GPU acceleration and see if it helps. See https://helpx.adobe.com/lightroom/kb/lightroom-gpu-faq.html.
Also, make sure Lightroom is up to date: https://helpx.adobe.com/lightroom/kb/keeping-lightroom-up-to-date.html
Can you check what listed in the "Application" events for Lightroom in Windows 10's EventViewer? See http://www.dummies.com/computers/operating-systems/windows-10/how-to-use-event-viewer-in-windows-10/ for instructions.