Vista Inspirat is a legitimate software, but it might cause some problem with the Shell and GUI files. Depends on your luck, if you encounter any problems you can unintsall it or perform a system restore.
And you are most probably using 32-bit. You can check by going to Start >> Right click My Computer.
the reason was because a year ago or so... i installed vista transformation pack. A fews after that, i tried to put on my pc and it would just freeze at the bott up screen or or log on screen. The monitor would look all blurry and stuff. I had to reinstall XP and i lost all my info.