Hi,
It may be worth running a more extensive test on the Memory than is available from the bios diagnostics - you can do this as follows.
First, download the Memtest Image file ( .ISO ) on the following link.
http://www.memtest.org/download/4.20/memtest86+-4.20.iso.zip
This is a zipped file, if you don't have an extraction utility installed, download and install 7-Zip. Please note, if you have a 64bit installation, download and install the .msi 64-bit x64 installer on the link below.
Then, right click the zipped file, select 7-Zip, select extract files and then click Ok. Open the newly extracted folder to find the Memtest Image.
You will now need to use an application such as ImgBurn to burn the ISO correctly to a blank CD - a guide on using ImgBurn to write an ISO to a disc is Here.
When you have created the CD, shut down the notebook. Tap away at the esc key as you power on to enter the Start-up Menu. Insert the Memtest CD. Select 'Boot Menu options' ( f9 ), use the arrow keys to highlight the CD/DVD drive and hit enter to boot from the disc.
Run at least 3-4 passes and see if any errors are detected.
Regards,
DP-K