This shouldn't require a system restore.
When you used the registry cleaner, you broke some connection between a unique (?) usb port driver and the device, but all you needed to do was to:
1. Plug the device into the USB port as normal.
2. Right-click 'My Computer' and select 'Manage'.
3. In the 'Computer Management' window, on the left pane under 'System Tools', click once on 'Device Manager'.
3a. In the right pane, right-click the top-most item (a computer icon with your user name).
3b. Select 'Scan for hardware changes', and let it scan (it won't take long). If it throws you into an install dialogue, go through the install with Windows, and you should be golden; else -->
4. In the right pane, expand the '+' sign under the following devices, in turn: 'Disk Drives', 'Storage Volumes', and 'Universal Serial Bus controlelrs'. 5. One of these will refer to a representation of the device, but it may be referred to by its nomenclature (model number or 'Sansa' or 'Fuze' or something similar), as a volume name under 'Storage Volumes', or as a 'USB Mass Storage device' under the 'USB controllers' item.
6. Ideally, it'll be under 'Disk Drives'. Whichever it is, right-click the item and select 'Uninstall'. Confirm the uninstall.
7. Go to the very top-most item (a computer icon with your user name), and select 'Scan for hardware changes'.
8. Let windows select the right driver.
9. You Sansa should show up as it's supposed to.

On second thought, it's easier to do a system restore than to do it the right way. So do a system restore.

-webbit

I say beware of Windows.. nothing good will come from it. :)