Depending on your computer's disk drive, you might be able to rip the ISO off your game disk and manually put it on a USB Hard Drive using a program like Wii Backup Manager. Then you can play them using a USB loader.
You might need to format your USB HD using WBFS Manager, depending on it's size. Wii ISOs are always either 4GB or 8GB, while converting them to WBFS significantly reduces the filesize (New Super Mario Bros Wii goes all the way down to half a GB!) The downside to this is that WBFS files can only be stored on a Hard Drive formatted for WBFS, which Windows can't recognize, requiring a program like the aforementioned WBFS or Wii Backup Managers to move games to and from the device. This also means that that device is now solely for Wii backups (though can partition it and format only one partition, but this is only practical if your device has a very large amount of storage space, at least 250GB.)