So I just bought a new GPU (Asus Strix GTX 750TI-OC-2GD5) and a PSU (EVGA 500W) and I didn't have any trouble replacing it with my older one (300W not certified), I just removed the old cables and placed the new ones, I didn't have any problems starting my PC with the new PSU and the OLD GPU (GT 520 2G) but then when I replaced the GPU my PC just stopped at the BIOS blue screen, I hear a beep afterwards but nothing other than that happens, I started my PC with my GT 520 to ask for your help, so please help me out guys ^^ Thanks in advance
PS : Some screenshots
http://imgur.com/a/QvBE1
PS : Some screenshots
http://imgur.com/a/QvBE1