I wanted to install Vista on my laptop that doesn't meet the minimum requirements just to see how fast or slow it would run. It's a 750 MHz with 256 MB memory. Vista setup refused to install since it requires 512 MB minimum, 12 GB HDD space. So, without modifying any setup files, I was able to use a sysprepped image of Vista to install on my laptop.

I had XP installed on my C:\ partition, size 6 GB. I didn't want to increase this partition to 12 GB since I only have 20 GB total. I formatted C:\, applied the sysprepped image to C:\. Of course, since the MBR still contained the XP bootloader, it would not boot anything. So I did a repair install from Vista Setup and did a Startup Repair. This installed Vista bootloader to MBR and Vista nicely booted up to the screen "Vista is getting ready to install for the first time....

After this, I got the GUI wallpaper but this screen gave me an error that the drive letter assignment had changed or something like that. The second time I got this error, I pressed Shift-F10 to bring up command prompt and it showed vista was on D:\. I realized Vista was assigning my active partition (BartPE) the C:\ letter. Thus, I booted to BartPE, made Vista partition active, reapplied the image, repaired the bootloader, and then booted up again and what do you know! I got Vista to complete the install process.

It's an old laptop but I didn't have any problem with drivers. It found all except audio, which I downloaded the XP version from Dell and Vista accepted these nicely.

Since it's Vlited (Media Center, system restore, etc removed; kept IE7, Windows Mail, defender, firewall), it's not that bad in terms of speed, despite an experience score of 1.0.