Yes, more guts
I ask myself why he want to run Vista on a 256 MB machine and to make it worst. There's somewhere a topic from somebody to ask to install Vista on a 128 MB machine
I know that experiment with Windows XP
12 MHz clock speed
20 MB RAM
63 MB Install size
This is the record. Are you try to break it
Keep this in mind: On that machine, Windows XP tooks 47 minutes to boot up in a 'usable' state. It tooks 23 minutes to open Word and 11 minutes to open IE6 and the internetspeed whas below a 14K4 modem

(nah, have 100 Mbit from Borft UT Twente)
I shame myself that I recommend to use 4096 MB with Vista and not any less. 2048 MB is possible, but not when playing Battlefield 2 and/or Crysis of such games.
Another question comes here out:
Is there a nearby future for the 32-bit version? No!
The roads for Windows Vista 64-bit are wide open. 4096 MB is the standard in later 2008 (I keep track on that). There are three classes of users and interact with yourself if it is worth to give it a try:
Entry level users:
Internet, mail, some media and typing a letter or making a spreadsheet.
Windows Vista Home Basic with a low budget system and at least 1024 MB RAM!
Windows XP should be better on old systems (mostly used by this kind of users)
Mid-entry level users:
As above, but they want to handle lots of digital media and editing a movie is not unknown. I should be possible at a reasonal speed. Old games (DirextX 8 games) mostly works perfect on these machines
Windows Vista Home Premium on a firm machine (costs around 800-1200 dollar=650-900 euro here in Holland)
Windows XP on the smae setup should be a better choice to gain speed and productivity!
At least 1024 MB RAM or much better: 2048 MB
Powerusers:
Like me and much other people here belongs to this group. Gaming at high resolutions and don't want to make consessions with settings. Thes systems are expensive and only for the hobbyist. Much RAM, a fast graphic card and a fast processor combined creates a fast system to keep real 3D entertainment at home. Also this system can be used for typing a letter.
At least 2048 MB RAM and much better: 4096 MB or above.
There he is. "can I run Vista with 256 Mb?" or better "Does my computer fit on a bycycle for transport ? "
Don't waste much time, just my intention