Help Backing up ipad to itunes

[pedruid]

I have spent about 6 hours trying to back up before downloading IOS8. I currently have Version 7.1.2 (11D257). The problem appears to be my change of email which I did at the beginning of 2014. My password is acceptable when purchasing Apps from i Store but every time I elect to authorize my PC I am confronted with my old email address with the password blank. I enter my correct email and password but then iTunes tell me that my PC is already authorized. When I try and proceed I get this message displayed "Some of the purchases on the i Pad (my name), including ** could not be transferred to your iTunes library because you are not authorized for them on this computer. For a list of files that could not be transferred, click the + below". I have 91 total problems such as (TuneinRadio, Skype,Supersport,GoogleEarth etc,etc)
Please can anyone out there HELP me. PM me if it's more convenient.

 

[fxit_man]

You will still have your purchased apps in your account, and can download them when you are back on iOS 8, free of charge.

 

[pedruid]

You will still have your purchased apps in your account, and can download them when you are back on iOS 8, free of charge.

Thanks very much for your input, however, I just went ahead today and updated to IOS 8.

 

[fxit_man]

Thanks very much for your input, however, I just went ahead today and updated to IOS 8.

Great stuff!