I have a samsung r510 laptop and have installed windows 7 64 bit edition. All was good but now when i attempt to boot up it goes to a black screen and nothing else happens. When i attempt to boot in safe mode it hangs at classpnp.sys. I have tried using the system repair on the hd and on the dvd but nothing works. I have removed the hd and connected to my other laptop because i want to transfer some photos but all it does is freeze my other laptop. I have also tried to do a clean install but all it does is hang. Im pulling my hair out!!! Any ideas????