Dell Inspiron N5010 8 beeps after start-up

Hello,

yesterday, while playing a video game, the game client suddenly froze, although I could still move my mouse. After about 10 my screen turned off and computer started making 8 beeps in periodic intervals. I tried to look the solution up myself.

First thing I tried was cleaning the connector at RAM and pressing power button for 10 s with battery out. This did not help, so I decided to plug in my TV through HDMI, which did not help either. However, when I plugged in monitor from my desktop, notebook booted up normally without any problems. After about 3 hours (I did nothing special with it during this period of time) I plugged in my TV via HDMI, and the same problem appeared again. 

This time, after plugging in my monitor, only safe mode could be started. Starting it in normal mode would only lead straight to the blue screen. I tried to update my graphics card driver, only to get error message about failing to detect the card. Also, after starting freeware program CCleaner, which would normally display my computer preferences (processor, RAM, OS, Graphics card), graphics card information were nowhere to find.

My last resort was disassembling the notebook, and replugging the LCD cable, what did not help as well.

Is there anything else I can try, or should I go straight to the professionals to get it fixed?

Thank you in advance for your response.