Hi folks. Recently I have bought the new Geforce 8400GS 256mb graphics card. And I have install that in my Lenovo IBM Thinkcentre s51 8171, and after this installation of Graphic there in my system, the System fail to boot the Screen shows blank screen and a continues beeping. I have try many thing but still I have not completely overcome this issue. If you guys have any ideas or suggestion for the thing then please let me know. Your reply will be thanks and appreciated.