Dell Inspiron 14z 5423 [MAJOR ISSUES]

This is going to be quite a long description. Flashback to about a year ago. My son and I were trying to hook up his computer to a dell external monitor. It only provides hdmi output, but we had a USB to the phone line thing. We thought we could hook it up by connecting the computer to the monitor with the phone line port in the computer to the USB port on the monitor. MAJOR MISTAKE. The whole computer when black. The screen wasn't lit, but the power indicator was on. Nothing else. We ended up fixing it, but don't know how anymore. Before we did this, on startup, we saw the black screen with Dell Inspiron on it. Afterwards, all i see is lines on the screen.

Now fast forward to now. Recently (last 8 months) when I turn on the computer, I get the lines on the screen and I hear this beeping. Accidently happened in a library. Librarian thought I had a bomb or something I was able to fix it by connecting the computer into a external screen by the hdmi. The screen would then light up.

Then a couple hours ago, all broke loose. I went into my room, hit the power button and got a response of the same lines on the screen, but a beeping. But then I noticed several more but different now green colored lines on the left side of my screen. I took it to my tv thinking that would fix it and got the computer screen up on the t.v. But not on my pc. Still beeping and not lightning up. I looked up on the internet some solutions and I decided to boot my computer in safe mode by using the msconfig in run. I selected safe mode and restarted my computer. Well, now I don't hear the beeping, don't see anything on my t.v. And the same lines on my pc. I realize now that booting in safe mode results in not working with external monitor. I feel stupid. Any help would be great, Unfortunatly I think the computer is done for. Please help as fast as possible. I have exams I have to study for tommorow and my notes are on the pc.