The reason you don't see this addressed by Apple is that it is very likely specific conditions on the user end.
Temporarily, try turning off your computer's anti-virus software and/or disabling firewalls (both your Windows firewall and router firewall ... you only need one but some people have both up). Strangely enough, you may also need to make sure your router's firmware is up to date, and I think some people resort to bypassing their router entirely (i.e. Ethernet from computer to modem).
Disabling firewalls is one of Apples's first instructions and I've tried that suggestion. Are you telling me that even though only a small number of iPad owners are dealing with this issue, Apple doesn't have to deal with it and we are on our own? Even those who are contacting Apple aren't being helped. So what do we do.. is it our tough luck now? I have no interest in jail breaking, all I want is to be able to use my iPad and enjoy it to its' full functionality.
If you have an iPad 1, the max iOS is 5.1.1. For newer iPads, the current iOS is 6.1. The Settings>General>Software Update only appears if you have iOS 5.0 or higher currently installed.
iOS 5: Updating your device to iOS 5 or Later
How to install iOS 6
iOS: How to update your iPhone, iPad, or iPod touch
If you are currently running an iOS lower than 5.0, connect the iPad to the computer, open iTunes. Then select the iPad under the Devices heading on the left, click on the Summary tab and then click on Check for Update.
Tip - If connected to your computer, you may need to disable your firewall and anitvirus software temporarily. Then download and install the iOS update. Be sure and backup your iPad before the iOS update. After you update an iPad (except iPad 1) to iOS 6.x, the next update can be installed via wifi (i.e., not connected to your computer).
Thanks Tom, but these instructions were the first things I tried. I need to hear from one of the "few" people who are experiencing this issue. This is my first experience with an apple product and it has been terrible. Imagine having to run Windows 98 on your pc, because you can't upgrade any higher. I have to say I'm happy with the functionality of this version (4.3.5) but what is frustrating is my ability to download apps - for instance I was so thrilled to see a Rolling Stones app, but I need at least a 5.0 iOS. When I tried to do a restore, I was unable to use several of my apps because they now required the higher IOS. My iPad seems to be a lemon, and it stinks that I am stuck with it.