BSOD on initializing chkdsk, no cursor, few rows of colored garbled pi

Hello all, I tried to do a routine (once a year) chkdsk via the command prompt Code: --------- > chkdsk /r > shutdown /r /f /t 1 --------- . And upon the reboot, all I get is a black screen, no cursor, with ~4 rows of rainbow, garbled pixels at the very top of the monitor (certain pixels occasionally change colours). This occurs before the windows splash screen. I have left the computer...