Right after rebooting my computer (Windows 7 Pro) I can open one photo file in CS6 using any normal method of opening a file in Photoshop. After closing that file I cannot open any more files using any method such as>Open Recent, File>Open, or right click open using Photoshop, by selecting the file, double-clicking to open it etc. I also cannot open a file in photoshop CS6 from Lightroom 5 using Photo>Edit In> Photoshop CS6. Everything works in Lightroom when I use Photo>Edit>open in CS6 Photoshop opens but the file doesn't.
If I reboot my computer I can then open one file using any of those methods, but when I try to open an additional file it will not open. I have run through all the opening Photoshop without plugins suggestions and all the other suggestions about what may cause this problem which I have found on Photoshop Help and Support Center and nothing has worked.
This started while Lightroom 4.4 and CS6 were on my machine and had been working well for months. Then, suddenly, I couldn't open anything in Photoshop. I know of no changes made to the computer. After trying various suggested solutions I reinstalled Photoshop CS6 and things seemed to be working so I went ahead with updating to Lightroom 5. The same problem popped up in CS6 again. Lightroom 5 and Lightroom 4.4 have both worked with no problems and still do. Photoshop seems to be the problem. I've also run an antivirus which found nothing.
Any suggestions?