Screen problem (blinking black stripes)

Hi,

I'm facing lately with following issue. Everything works fine but sometimes (periodically but not on a regular basis) on my desktop are showing black stripes on white background (especially during surfing the web with complex graphics such as those based on flash).

It is annoying and not healthy (it is blinking and I suppose it is not good for eyes)
 And i am affraid that could injure my hardware.

I've try the following:

- delete and reinstall flash
 - turn from Unity to gnome (even in "without effect" version problem still exists)
 - install system from scratch
 - I've tried on 3 different browsers (Opera, Chrome , Firefox)

neither of the listed above had helped.

Interesting thing is that I have not noticed this Issue when I was playing movie with SMPlayer.
 Only in web browser (in listed above: Opera , Chrome and FF) and when I tried to change Background image in Unity.

I hope this information is sufficient.

Thank you in Advance for solving this Problem.

Regards

ProblemType: Bug
 DistroRelease: Ubuntu 12.04.2 LTS
 ProcVersionSignature: Ubuntu 3.2.0-37-generic-pae
 Uname: 3.2.0-37-generic-pae (i686 i686 i386 GNU/Linux)
 Hardware:
 Mobo: Gigabyte G41-Combo
 Graphics: Intel Corporation 4 Series Chipset Integrated Graphics Controller
 Monitor: LG W2241S-BF (wierd thing is that Ubuntu sees it as Goldstar Company 23"- and it has 22")