The green light next to the cylinder is your HD activity light and i assume the other is "power on"
so more details , like make of PC, just exactly what it does, do you see anything on the monitor.....etc?
youmay want to check the bios settings to see if the HD is being detected, usually press F1 ,F2 or delete at boot.
you may want to run memtest86
DL from here
the prog will make a bootable floppy. Put the floppy in the drive, reboot , go to the bios, set the bios to boot from floppy, exit and save bios, the pc will restart and boot from the floppy.