I didn't see any reply as to 32 or 64 bit on menoumeanou;s laptop? If it is 32 bit then it is a straight forward download and the Vista driver should work.
However if he has a 64 bit system it is a nightmare as Nvidia do not support any Sony laptop and reccomend download from Sony and again there is no 64bit support for the Geforce 8400M graphics card!!.I had this problem but I did eventually succeed in getting a driver to run on my VGN-AR61M laptop,and this how I did it.
1.Download free driver sweeper and analyse you system.( I used 'Driver Fusion')
2.Remove all traces of any Nvidia drivers from your system
3.Download Mobility Modder (Free driver modder.Make sure you get the Nvidia version.
4.Download the driver for your card from Nvidia.(I used 296.10 64bit for win.7 @Vista.
5.Run the download so it loads into a Folder on your hard drive.(mine was under my C drive Nvidia)
this attempt will likely fail!! Don't despair.
6.Now open the Modder programe and browse to C/Nvidia and open the driver file,then run the Modder programe.It will add or remove several file and stop.
At this point you can try running the driver again you may be lucky.(I wasn't!!)
7. Now the stroke of genius I looked at the PCI/VEN in my 32 bit driver on my vista 32bit system.(Ihave a dual system on my laptop) I noted down the PCI/VEN Numbers.I then opened the 64 bit windows 7 sytem and browsed to the downloaded and now modded Nvidia driver file.I opened the folder and opened it until I found the driver file.I opened that and then opened the RAR file it opens in notepad.I went down the file until I found the lines PCI/VEN with several numbers in each line.I beleve there were five lines.I went through each line ammending it to read the same as my 32 bit driver.In mycasethey were as follows.
sorry I do not use skype.I will try to make it easier for you.If you are useing 32bit Windows go to the Sony support site and download the Nvidia driver from the Vista update section in your models support/download page.
If you are useing 64bit then there is no support for the Nvidia graphics card, so you must try to download one from Nvidia and in my case the one they recommend does not load up.It gives an error report CANNOT FIND COMPATIBLE GRAPHICS DEVICE.! iF THAT IS YOUR PROBLEM YOU MUST MODIFY THE DRIVER.I downloaded 296.10 and modified the NVAR FILE .
1. Go to Nvidia driver download and save the file to your downloads folder.
2. Go to Start / Computer/C/user/downloads
3.Find the downloaded driver double click and it will load into your hard drive.
4.It will most likely not load and give the error CANNOT FIND COMPATIBLE GRAPHICS DEVICE.
5.Close all open folders.
6.Go to Start/Computer.Click to open C drive (Or whichever is your operating drive.)
7.At this point you may see a folder called Nvidia if not open your programes folder and scroll through until you locate Nvidia.
8.Open the folder it should say Winvista 64.
9.Open that folder it should say 296.10
10. Open that folder and you should see IS.
11.Open that folder and you should see a long list of folders.
12. Open the first folder Display you should see another long list of folders.
13 Scroll through the folder until you find NVRAR
14.Open NVRAR it should open in notepad.
15.Scroll through until you see a list of lines like those in my first reply i.e PCI/VEN --------------
16.Replace those lines with those in my first reply above.
17. Close the programe.
18.Go to C/ Nvidia and run the driver setup file.
19. It should now load the driver and you will have Phsyx and Nvidia in control panel.