Move purchased iPad apps to Windows iTunes

I'm trying to upgrade my iPad 2 from 6.1.2 to 7.1. I connected it to my Windows Vista Home Premium computer which has iTunes 11.1.5.5 on it and backed up the iPad tp iTunes. When I tried to update the iPad I got a warning about there being Purchased Apps on the iPad that needed to be moved to iTunes before the update. I then set a password to encrypt the backup since I actually do want to keep the passwords and accounts if possible. I still got the message that there were purchased apps that I might want to move to iTunes before upgrading. I'm trying to find out how to do that and it's NOT going well. I searched Help and the Forum using the phrase in the message I got and many unrelated results were returned. Now I just wish I had backed up with a password the first time since I've wasted hours doing 2 full backups, I hope, and I still can't reliably upgrade. I was hoping to be recovering by now. In case it matters, I'm doing this on a different copy of iTunes than I used when I got the iPad originally. That Windows 7 Home Premium machine Blue Screens (Fails) almost every 10 minutes so using it is not a viable solution unless I can fix the Blue Screen issue first or do a factory reset on it and start over. The later would still result in an iTunes that is different than the original. In addition, it's been over a year since I last connected the iPad to a computer at all other than as a charging source when a better one wasn't available. During that time a great many changes have occured on the iPad that no iTunes was directly involved in since I was backing up to the iCloud rather than iTunes. Since I have a 64GB iPad with 10GB of available space and a 15GB iCloud accounrt that holds 9GB backups I'm reasonably sure that there's a considerable amount that isn't getting backed up to the iCloud or anywhere else. If I'm going to loose data I'd like to be able to know what's going away and decide if I wanrt to do something to save it first. That's the only reason I backed up to iTunes in the first place. I've read numerous horror stories about the iOS 7 series doing all manner of damage to previously well behaved iPads and I wasn't interested in being on the Bleeding Edge. I want as much of my data as I can get and an escape route if this iOD 7.1 thing doesn't work out. When I discussed this with someone with more Apple experience than I'll ever have I got the suggestion to back up using iTunes prior to upgrading. That's how I got to the point at which I now am stranded. I use my iPad nearly all day every day and am alerady missing things that should be in there because I don't want to change anything that would altrer it from what's backed up already. The sooner this is fixed, the better I'll like it.

One more thing: I'm not seeking to sync a significant portion of what's in iTunes to the iPad. I bought the Match service and it stopped accepting new items so now I'm keeping it until either I get it working again or get an acutal home for what's in it. It doesn't seem to want to download to the new iTunes even though it's an Authorized copy and can see the content. I've developed other methods to get the audio and video content that I want onto my iPad so Match isn't a requirement for me at this point. If sync is required to get these apps transfered then I have no problem with that as long as I can avoid transferring the wrong things in either direction.

I'd welcome any help anyone is willing to provide. Questions are welcomed as well. I tried to provide relevant information in my description above but know that I could very well have left out something that is significant but I didn't know that it was and my not know how to find the information. If you have questions, please ask them and I'll asnswer as fully as I'm able. If I don't know how to get the needed information, that will be my response and I'll be depending on someone to provide some directions. On the iPad, I think I'm at an intermediate level so I do know where quite a few things are.

Thanks for any help that's provided.

Paul