I can't restore my iPhone from a backup?

My phone was jailbroken and I wanted to update it to IOS6. I backed it up and then restored it from the backup to unjailbreak it. When it was done restoring, I got an error message saying that it couldn't be restored from the back up. Also, I can't find the location of ANY of my iPhone backups. I've already searched online and found specific directory locations but my computer says that the location doesn't exist. I NEED MY TEXT MESSAGES BACK. Can anyone help me?

Added (1). I tried the link and it wouldn't detect my phone. Besides, I want to try to do it without any kind of special software first. Also, after my phone is restored, it says something like "iPhone could not restore from backup because backup could not be saved on computer", but I can see the backup files on my computer…

What you can do is to go to this link http://www.mypcbackup.com/ and it only costs 5 to 6 bucks a month and you can back up not just your IPhone, but also your entire computer and it enables you to update your IPhone even if it's jailbroken and you can send all your files from your computer to your phone or vise versa.

Try connecting your iPhone using a different USB port on your computer and then restore from backup. Right click on your iPhone under Devices in iTunes and click Restore from Backup. You can then choose which iPhone backup you want to restore from.

Also, you can browse your iPhone backup and extract your text messages from backup using this program
http://www.wideanglesoftware.com/ibackupextractor/

Hope this helps.