I using Windows 7 After the PC didn't start a few times, it suddenly did, but when it happened, some applications that access the file system didn't work.
Dropbox popped up a message saying there's a problem with my FS. Using the Microsoft Image Viewer by double clicking an image, it says it could not open the file, but paint works for some reason.
Apps opened with Administrative access can access files as usual. My user name is among the users in the permissions for both the main drive (Desktop, Program files etc.) and another drive.
Why could this happen? What should I check?