Just to add Dmex,
Is there any advantage or disadvantage to running 64-bit Windows on a system with only 1-2GB of RAM?
I haven’t specifically tested this, but I certainly wouldn’t recommend Vista x64 on a system with 1GB of RAM. With 2GB, it’s probably a wash and only worth doing if you are certain you will upgrade the system to 4GB or more.
Because there’s no upgrade path from 32-bit to 64-bit Windows, this strategy avoids the need to reinstall the operating system from scratch and migrate all your programs and data files after completing the RAM upgrade.
Upgrade path available from 32-bit to 64-bit?
There is a upgrade path available for those who have purchased Windows Vista under the retail channel, unfortunately manufactured desktops/laptops with preinstalled OS miss out on this one, But it is available through the following website for a small fee of about 15-17$ AUD.
Windows Vista Alternate Media