My wife has a Dell XPS-15Z laptop purchased in January 2012 with Windows 7 installed. Starting in the last couple days, when she wakes it out of sleep/hibernation, there is a black screen with "Operation System Not Found" in the upper left corner. Hitting escape causes Windows to open normally. It functions normally except that the fan is running pretty much all the time and the case feels hot to the touch around the hard drive and vents. When she reboots from a complete shut-down, both the error message and fan don't seem to reoccur.

The laptop is still in warranty, but we were wondering what may be causing this and what we may be looking at in terms of repairs.

Thank you.