Windows failed to start with new RAM stick

My laptop has got 2GB + 1GB of RAM. I just bought a new RAM stick: Corsair 2GB DDR3 PC3-10*** (I don't remember) in order to have 4 GB of RAM. So I removed the old 1GB stick and I put the new 2GB stick, then I turned on my laptop but Windows failed to start. I saw the "Windows is loading files" screen and then it said: Windows failed to start etc.. Open Startup Repair or Start Windows normally. If I open startup repair, it says there's no problem, if I choose Start Windows normally, 1 time out of 10 it boots correctly, the other times it shows some odd errors like: kernel is missing or corrupted, NTFS module is missing, other files are missing or simply it goes back to the Windows is loading files screen.
I made some tests and these are the results:
new 2GB stick + old 2GB (this is what I'd like to have) = Windows failed to start.
old 2GB + old 1GB = Windows boots normally.
new 2GB + old 1GB = Windows boots normally.

As you can read, the new 2GB stick is working fine, but Windows won't boot if it is mounted together with the old 2GB stick.

What can I do??
P.S. Linux boots normally with old 2GB + new 2GB.

HarriePateman said:

Your model of laptop has a maximum ram limit of 4GB so its not that.

Can you try this please,

-Test your RAM modules for possible errors.

How to Test and Diagnose RAM Issues with Memtest86+

Which stick(s) should I test? Only the new one or old and new 2GB together?

HarriePateman said:

The 2 sticks you wish to use :)

Ok, I'll run the test tomorrow.

HarriePateman said:

Okay brilliant, it may be worth doing over night as sometimes it can take 20+ hours.

Unfortunately I won't have my laptop with me until tomorrow, so I'll run the memtest tomorrow night.

HarriePateman said:

Tomoms said:

HarriePateman said:

Okay brilliant, it may be worth doing over night as sometimes it can take 20+ hours.

Unfortunately I won't have my laptop with me until tomorrow, so I'll run the memtest tomorrow night.

Okay thanks for keeping us updated :)

I woke up an hour ago and stopped the test. These are the results. 7 pass, 0 errors. So I guess my ram sticks are ok. What could be the problem then?

News: I removed my graphic card driver, then I rebooted and waited for Windows 7 to install its built-in driver - 'cause I've read that could be the problem. This workaround worked for the first 2 boots, but now the issue is here again :-(