Vista does not recognize my powershot a85 cam .. The error it is giving out when i connect the usb cable is 'USB Device not recognized' . It does not display in the my computer box . any ideas ?

hi Markaz.
you can try is to open Device Manager, expand USB Serial Bus Controllers, right-click on USB Root Hub and then click on Properties. Click on the Power Management tab and uncheck the Allow the computer to turn off this device to save power box.
or read up more at this link.
How to Fix USB Device Not Recognized in Windows

What do I do if my USB device is not recognized? Method 4: Reinstall USB controllers.

1. Select Start, then type device manager in the Search box, and then select Device Manager.
2. Expand Universal Serial Bus controllers. Press and hold (or right-click) a device and select Uninstall. ...
3. Once complete, restart your computer. Your USB controllers will automatically install.

Error: "USB Device not recognized" when you try to access a USB ...

https://support.microsoft.com/.../error-usb-device-not-recognized-when-you-try-to-acces... Search for: What do I do if my USB device is not recognized?

or this link.
Windows does not recognize the USB device Google Search

Consider NOT connecting your camera to your computer.

The best way to download pictures from your camera to your computer involves removing the memory card from the camera and plugging it into a card reader (either built-in to the computer or connected via USB or FireWire). This is likely to be faster than connecting the camera to the computer, and won't run down your camera's batteries.

Once the card is plugged in, it will appear to your computer as a removable drive. You can use the operating system's drag&drop facility to copy pictures from the card to the computer's hard drive, the same way you copy any other files. Or you can use iPhoto or any other photo cataloging program.

In the short term you can take the memory card out and use a card reader - at least that will let you see the pictures.

Use a card reader instead of your camera.

Consider NOT connecting your camera to your computer.

The best way to download pictures from your camera to your computer involves removing the memory card from the camera and plugging it into a card reader (either built-in to the computer or connected via USB or FireWire). This is likely to be faster than connecting the camera to the computer, and won't run down your camera's batteries.

Once the card is plugged in, it will appear to your computer as a removable drive. You can use the operating system's drag&drop facility to copy pictures from the card to the computer's hard drive, the same way you copy any other files. Or you can use any photo cataloging program.

I have had that problem with other USB devices i suggest trying a different USB port as the USB port you have used to connect the X3 to is most likely malfunctioning.

1. connect U r camera to Back side Mother Board USB Port not for extension or front side port.

2. Check in bios USB controllers are enabled or disabled. if disabled enable it.

3. in windows device manger check for usb controllers

Turn off the CPU unplug the power cable and all usb cables, let it sit for about 15-20 minutes. Plug power cable back in, turn on CPU, plug in your usb devices.

try connecting your phone to a USB 2.0 port.
Some older computers give this error. If you can find a newer laptop to try and plug it in it may recognize it. As far as a driver goes, with Windows XP or Vista you shouldn't need a driver disk at all. It is more like a compatibility issue than a software problem.

sounds like a bad usb cable