I had a Vista Home Premium 32-bit running on an Acer 4420 Extensa. I ran the Windows 7 RC in virtual PC and I was never able to find a graphics driver that would work for my ATI Radeon graphics card as it was discontinued apparently. Anyway, I purchased the Windows 7 Home Premium upgrade media. For giggles, I installed it on a clean partition on my laptop and it activated just fine (32 bit). I then set up a dual boot with Vista and 7. After running Windows Update, a working driver for the graphics was installed and it worked. After I thought about it, I decided keeping Vista was a waste. Soo... I wiped the whole hard drive and installed Windows 7 64-bit from the upgrade media instead of the 32 bit and I am glad I did...not one issue. Reinstalled many of my apps via Ninite Easy PC Setup and Multiple App Installer - Great For Win7 Upgrades, reinstalled Adobe Creative Suite, Office, and a few others. It was a rather painless experience. Just thought I would share.