In Develop Module, on the left hand side, look at the history panel. If nothing shows there (other than Import) then there probably isn't any preset applied. Also, in the Basic Panel on the top of the right hand side, all the sliders should be in the middle if no preset has been applied.
As Francisco said, most likely you're seeing the normal process. At first, Lightroom briefly shows the jpeg preview that's embedded in the file. This will be the same "look" as the camera maker's normal jpeg processing. Then Lightroom shows you its own rendering of the image.
Are you shooting raw? If so, remember that every raw convertor does it slightly differently. There's no single "right" way to render a raw file. Adobe default rendering is their profile called "Adobe Standard", but Adobe also provides "Camera..." profiles (Camera Standard, Camera Landscape etc) for Nikon, Canon and a few other camera makes, and these profiles are designed to mimic the corresponding profiles from the camera makers.
If you want use these, then in Develop Module, if you go to the Camera Calibration tab (bottom right), see if there's a choice for "Profile". If so choose the one that's closest to the picture profile setting in your camera (Standard, Landscape or whatever). That will probably be close the preview you see briefly.
