I am exceedingly new to photoshop. As in I have only had it for about four days. I have been using it as a drawing program. Anyway today I was drawing and I saved my file, but I was in a rush and had to turn off my computer, so I just held down the power off button and didn't exit out of photoshop as I never had to worry about corrupt files when I use Paint tool Sai so I assumed it wouldn't affect my PSD since I had remembered to save it. Anyway about an hour and a half after this happened I go to photoshop to work on my drawing and it's saying "Could not complete your request because it is not a valid photoshop document." I don't know how to get it back and I've been looking it up for the past few hours, trying everything and am having no luck. I've already reset my prefs and looked to see if it is in another place and such but it's not that. I really, really, need this file back. I've worked on it all day and I'm really hoping I can get it back?? Does anyone have any solutions? Please and thank you.
I doubt whether you'll get your document back. As you've discovered, you need to save your artwork properly. You should also make incremtal backups, both internally and externally.