Seems to be a graphics card or monitor issue. Graphics card
shouldn't be dead, otherwise you will hear beeps when booting
up.
Do you have a spare computer? If so, try the following.
1. If you have an external graphics card, remove it and plug it
into the spare computer. If it works fine, test scenario 2.
2. Repeat for the HDD. Ensure that only the HDD is plugged in to
the spare computer. The rest of the hardware you have to use back
your spare computer's hardware. If it works, test scenario 3.
3. Plug in both the affected computer's graphics card and HDD to
the spare computer.
If either of the scenario doesn't work, report back.
