My first task was getting a version of Windows installed. The tablet came with Vista on it. It also came with a registered(!) copy of OneNote - free plug for Gateway here, that's quite a value IMHO - and some other "real world" software preinstalled. Adobe Acrobat, Real Player and some Gateway unique software. My first temptation is to wipe the machine and install Vista "clean" - no third party software at all. That definitely helps with testing since any bugs I find would not depend on any conflicts caused by those utilities.
But that is not real world. Machines ship with these utilities, and while OneNote has no great number of dependencies, I still need to verify we have no conflicts. After installing some basic tools we all use (bug tracking software, a lightweight debugger (http://www.microsoft.com/whdc/devtools/debugging/installx86.mspx) and some other basic applications I know I will always need, I made an image of the hard drive so I can restore the machine to it's original state any time down the line. Once I had that, I installed Vista 64 bit and imaged it, Vista 32 bit (clean this time), imaged it, and will get XP loaded next. Now I will be set up for testing for quite a while.
"We need to focus on 64 bit testing next week? No problem, I'll restore my image."
"You want me to install the German Language Pack on Windows XP and verify dialogs and strings? No problem, I'll restore my image and go."
"You need to dogfood some right-to-left language , you pick, Hindi date format (use Urdu language settings at this point?), 133 dots per square inch screen resolution using high contrast, with a 56K modem, Office Home and Student on Vista Home Basic and add a tool to increase network latency to 5 seconds? I'm on it."
And so on. Wiping and restoring images gets to be routine.
Comments, criticisms, questions and concerns,