To find out if whether you have a 32-bit or a 64-bit system:
Insert this line in your control panel address bar:
Control Panel\System and Security\System
Note: to get to your "control panel" you can insert "Control Panel" in a regular folder address bar. "Control panel" can usually also be accessed from the "start menu".
If that doesn't work you can press "win+pause" buttons on your keyboard to open the same window.
win = button with a microsoft flag
pause should be close to your numpad; often above page up and page down buttons.
Other than that.... the latest version of tortoise SVN is often the best choice.