Follow theses steps for install driver & service :
- You need to install the VirtIO Balloon Driver and the management service
- Verify you have install driver voer Balloon in Device Manager
- Click on Reinstall and select lastest virtio CD
- For windows 2008/W7 : Copy d:\WIN7\AMD64\BLNSVR.* virtio.iso to "c:\Program files\VirtBalloon"
- Then launch this command c:\Program files\VirtBalloon\BLNSVR.exe -i