I have a 32 bit machine with windows 7, I need to install hadoop and try it out, I checked Cloudera distribution and it is for linux, VMWare images with 64 bit processor. H
You can install Hadoop on windows if you install cygwin see http://ebiquity.umbc.edu/Tutorials/Hadoop/00%20-%20Intro.html Also Microsoft is working with Hortonworks to bring Hadoop to windows properly but for now it is only available on Azure. I understands there are plans to make it available on windows in general in the future.