Hi Roy,
In general terms, 64-bit Windows can run both 64-bit and 32-bit
applications.
64-bit Windows cannot run any 16-bit applications; including both 16-bit
Windows, and MS-DOS applications. This also includes 16-bit Installers
for 32-bit applications, or 32-bit applications which load 16-bit
components.
See here for more details:
http://support.microsoft.com/kb/896456
It's not clear from your post if you're thinking of 64-bit Windows XP
(since this is an XP newsgroup); or a more recent version of Windows.
The 64-bit features of Windows 7 are vastly improved over 64-bit XP,
where 64-bit support was still a bit primitive. 64-bit Windows will
allow you to use more than 2GB of RAM; so if your new laptop has, say,
4Gb RAM, you'd really want to run 64-bit; and preferably, Windows 7
rather than Windows XP.
I'd assume if you are buying new hardware, it will likely come with 64
bit Windows 7.
For driver support, you would want to check with the vendor of the
laptop you intend to buy - most hardware-specific drivers for the
computer itself will come from the manufacturer; not off the Microsoft
DVD. But in general terms, 64-bit Windows 7 has fairly good driver
support built-in, for all current popular hardware. You may have trouble
finding drivers for devices (printers etc) which are more than a few
years old.
Keep that carbon fibre away from any naked flames. It would be sad to
see it adding to your CO2 carbon footprint
Hope this helps,
Andrew