Just like in Windows 1.0 to XP when a new video driver is installed it can forget your old settings.
You didn't tell us if you set the video mode to your preference.
I recently bought a Lenovo Y410 laptop, with an Intel Graphics Media Accelerator X3100 graphics card. When prompted to download Windows updates, I also selected to download an optional update described as follow: 'Intel Corporation driver update for Mobile Intel(R) 965 Express Chipset Family'. Just to give a more complete picture of what I did, I went on to install the programs Avast and Spybot and only after these did I restart my computer. On boot-up Avast ran a check on my system before the OS loads fully (Vista is pre-installed).
When Vista has loaded fully, my graphics go haywire; everything assume bigger sizes: the icons, the font, the Start bar menu, and websites need lateral scrolling now.
I assumed it had nothing to do with Avast or Spybot, so I thought of 'rolling back' the driver for my display adapter but that option was greyed. So I tried installing the driver from Lenovo's site even though I was prompted that the driver I was downloading is an older version than the one I currently have.
Alas, 'big' is still here to stay. Things get more complicated for me because I'm still not used to Vista's layout and the non-familiarity really saps my energy.
Any help or suggestions please?