Help, Wrong Display on A150-aw ZG5

This machine is my friend's, who changed the wlan card to a dell one and installed osx on it. It works well, and he gave this to me.
I changed the wlan back to the original one, added extra 256MB RAM, preparing to install XP, however the display went wrong.
Let's say there are 1024*600 point on the LCD, then the left 800*600 is showing things, the right 224*600 is dark.
Within the 800*600 part, the upper 800*469 display the original thing that should be displayed in 1024*600, the lower 800*131 repeat the upper part.
pic: http://photo.163.com/photo/jackallau/#m ... 042972&p=1
I tried without the extra RAM, didn't work.
I tried to flash the BIOS by using the Fn+Esc way, didn't work.
I tried to recover the original Linux, didn't work.
I tried to install XP and then install driver for the VGA card, didn't work.
I tried to install OSX again, using windosx86.iso, the left 800*600 is displayed right
pic: http://photo.163.com/photo/jackallau/#m ... 501281&p=1
and when the installation is done, I set the display to 1024*768, the whole LCD is displaying things, however I can now see the remaining part of 1024*168 below.
but when I reboot it, the problem is still there, it shows from the very beginning, where BIOS do its self test.
Can anybody help me please? Thanks.

 

I hope u can c the pics
sorry i dont no where i can upload pics and link it in the post.
but the album i'm using is 100% safe.

 

Has happened to me when I opened it and closed it back again.
Check the LCD cable, I'm 100% sure that it's the LCD cable! Take it out and put it back tightly.
BTW, why only 256MB?

 

Actually I tried it several times..... gosh, maybe i break it..... thx anyway, i'll try more times later.
I have a spear 256MB RAM, not bought for it, that why.

 

OK, u r right, I tried again, and it works
cant believe I spent meaningless hrs on it.

 

Bad Luck! it worked well for just 1 day, today the problem shows again...
I think I can only get it repaired, should i contact pcworld where i bought it, or should i contact Acer?
thx

 

If there is nothing visible to know that you have opened it, send it to Acer to get it repaired for free...
Of course take out the added RAM stick...

 

But I opened it, added the RAM, How I can make it nothing visible there?
I emailed pcworld support, they tell me to contact acer....
anyhow i'd like to stop by pcworld to see what happens.

 

I left it to pcworld, they will call me when it comes back from acer.
thx