Hello there. Can anyone help?

I have a Sony VAIO VGN-FE31Z. This was first shipped with XP. A few months later, I installed a Vista update onto a new partition. I lived with my dual boot very successfully until last week when I decided to upgrade to Windows 7. I did a clean install of Windows 7, wiping my Vista partition. Unfortunately, when I tried to install my applications (originally shipped with the Vista upgrade disk) an error message came up saying that the disk only worked with Vista.

I therefore clean installed Vista back onto this partition. In the course of this, following the Sony instructions, I updated my BIOS. Once Vista had installed, and I had then added Vista SP1 and reloaded my applications using the Sony disk, I then upgraded to Windows 7 again - in update mode, rather than a clean install.

When it came to enter my product key, I noticed that a couple of the laptop's keyboard keys were not working. But I was able to enter the code with a bit of persistence.

Unfortunately, once in Windows, the laptop keyboard continued to malfunction, with the K, S, A, B and M letter keys failing to respond, as well as the . key and the down cursor. I uninstalled the keyboard driver and rebooted. Windows found the keyboard and reinstalled the driver. However the problem remained after another restart. I therefore booted XP and observed the same problem - although the keyboard driver was ostensibly different. Finally, I entered the BIOS and noted that the down cursor was not working in that environment either.

I have today started to use a USB keyboard and it works absolutely perfectly.

I have reached the conclusion that the BIOS update must have caused a problem. But I might be wrong. Either way: does anyone have any suggestions?

I'm sure I should be leaving more system information. The BIOS version is R0172J3 - unfortunately I don't have the previous version number noted anywhere. All other specs are unchanged from factory shipping, except of course for the OS, as above.

Thanks for any advice.