When you say "3 separate ones" I assume that you mean that you found 3 separate backup files in your old backup folder. If so, you want to restore all 3 by restoring the entire backup folder and all of its contents.
Go to \Users\(username)\AppData\Roaming\Apple Computer\MobileSync\Backup\ and rename to existing backup folder to something like Backup.old (so it becomes \Users\(username)\AppData\Roaming\Apple Computer\MobileSync\Backup.old. Then, as Ingo2711 posted earlier, restore the entire Backup folder from your computer backup to your ts original location on your hard drive. You should now have these two folders on your hard drive:
\Users\(username)\AppData\Roaming\Apple Computer\MobileSync\Backup.old (your renamed current folder) and
\Users\(username)\AppData\Roaming\Apple Computer\MobileSync\Backup (the older folder restored from your backup)
Now open iTunes on your computer and go to Preferences>Devices and look at the backup list. It should now show your earlier backup(s) that were in the earlier backup folder that you restored from your computer backup. If so, you can now connect your phone to your computer, right-click on the name of your phone on the left side of iTunes (like the image posted above), select Restore from Backup and when prompted choose the earlier backup you want to restore to your phone.