i have a studio 1558 laptop with windows 7 home premium . when i start it, i get the "DELL SYMBOL" Studio and the blue line that loads partially and gets stuck. and after 1-2 min the screen becomes blank for 2-3 min. the cursor appears and blinks for and in black screen i get the meassge PXE:media text failure, check cable PXE-M0F : Exiting PXE ROM . Operating system not found. ...please help