I left Debian a while,and Debian give me a black screen despite I pressed keyboard and mouse

and when I reboot Debian,I stuck at BIOS Splash,seems like I unplug SanDisk CZ48 usb flash drive problem solved,can you help me figure out what does Sandisk CZ48,Debian,Award BIOS do during I left Debian?




maybe my Gigabyte Geforce GTX 650 TI BOOST is bad,I replace it with EVGA GT 740 SC 2GB GDDR5,hope this time problem solve.