Acer Aspire 7520 Slow Graphics Processing.

Greetings everyone,

I have an Acer Aspire 7520 that is 2 years old, the system specs are:

- AMD Athlon 1.8GHz Dual Core.
- 17" WXGA+ CrystalBrite LCD.
- 4 GB DDR2.
- 500 GB HDD.
- NVIDIA GeForce 7000M.

It worked fine for a year but starting the second year, the sound card started to fail, and by that I mean that the sound sometimes works and sometimes it doesn't, but I solved this problem by buying an external sound card.

Two months ago I accidentally hit the laptop in the wall and after that incident the Graphics card can't process anything that requires high or medium graphics for example:

-When I play 720p videos the video runs very slow, it should be noted that I used to play 720p withouth any problem before the accident.

-The Windows Experience Index for Graphics went from 3.4 to 2.0 after the accident.

-Games that used to run at 30-40 FPS, now run at 2 - 3 FPS max.

- Windows AERO runs very slow now, so I if I want to use windows I have to run Windows Classic theme.

Things I've done:
1) Format my PC and tried different OSs XP, 7.
2) Flash the BIOS.
3) Change the Hard Drive with another one.
4) Change the RAM.
None of these things worked.

Does anyone know what might be causing this problem?
- screen went bad?
- Graphics card went bad?
or ?