Q: iPad 1 disabled, not recognized when plugged in to any computer

Connecting in Recovery mode may also work: If you can't update or restore your iOS device

Did you try to erase it remotely via iCloud? Log into your iCloud account on your computer, locate your device and click on "Erase"

When you connected the iPad to your computer did you also run iTunes on your computer. It is through iTunes that you can restore your iPad.

try steps here iPhone, iPad, or iPod not recognized in iTunes for Windows - Apple Support

do steps under verify apple mobile device usb installed and see if that helps

No, check this:

Media you've bought from the iTunes Store or songs you've imported from CDs are saved in your My Music folder by default. They won't be deleted by removing iTunes. Although it's highly unlikely that you'll lose any of your iTunes Library when following the steps below, first make sure that your iTunes library is backed up. See iTunes: Back up your iTunes library by copying to an external hard drive for more information.

copied from Remove and reinstall iTunes and related software components for Windows Vista, Windows 7, or Windows 8 - Apple Support