sometimes corrupt display, memory/motherboard/? problem

[JesseKnows]

I received a T400 type 2768 with switchable graphics from a colleague some months ago (I don't know its history before then). I installed Win7 64 Ultimate. It came with 3GB, and I replaced the 1GB with 4GB.
All updates installed per Lenovo and Microsoft.
I have on-site support, ending 2013.

Here are the problems:
1) Windows Memory Diagnostics with any of the 4 sticks I have do not complete - freeze partway through.
2) With Energy Saving graphics (Intel) ONLY, I get strange video behavior on some applications. Google Chrome (and some others) has problem, Internet Explorer 9 does not. The behavior is that areas on the screen increasingly become squiggly and fuzzy, as if very small blocks of video memory are shuffled vertically. I just saw it on the ATI Catalyst Install Manager, in updating my driver from 8.792.5.1000 to 8.792.5.2000.

The video problem occurs with 1GB, 2GB, 4GB or 6GB installed.
I have never had a blue screen or application crash.
With High Performance (ATI) graphics everything is fine.
Display driver is Mobile Intel(R) 4 Series Express Chipset Family version 8.792.5.2000.

Lenovo first sent me a 1GB memory stick replacement (at the time a few weeks ago I did get through Windows Memory Diagnostics with just the 2GB stick). That's how I have 4 sticks (original 1GB+2GB, replacement 1GB, my 4GB).
When the memory swap did not fix the problem they diagnosed a motherboard replacement and sent a tech who did the replacement. That did not help either - memory test passed right after the tech was done, but a day later it failed again. The Chrome problem returned as well.

I just tried a clean install on another hard drive, the problem still occurred.

The tech who did the motherboard said maybe the bad motherboard broke my RAM. Is that possible? Should I ask Lenovo to replace their 3GB memory again? Or motherboard and memory both together?

Any idea from the experts here?

[emeraldgirl08]

EDIT:

I misread your post so I deleted my previous post

I have read that RAM could cause artifacts to appear in some cases. If you have access to other RAM to test I would suggest doing so. You mentioned that with ATI there are no artifacts while Intel has them. Intel is integrated and IIRC integrated graphics work with RAM as part of their ability to render graphics. This implies that perhaps the RAM are somehow involved in the artifact rendering.

What version of BIOS do you have?

[JesseKnows]

Thanks emeraldgirl08 for the reply, but I don't think you understood my question. I have all the drivers, both on my previous install and the new one I made for testing.
I completely believe it's a hardware problem. It's just very strange that both motherboards had it, with 4 out of 4 memory sticks, and never a crash or blue screen.

[Cigarguy]

Yep sounds like a hardware problem. Besides making sure that the RAM module is seated properly there's not much you can do. There's a remote possibility that all 4 modules are defective but chances are you'll need a new MB.