Open iTunes on your computer. Connect your device (iPad or whatever) to the computer. Hold both home and power buttons for exactly 10 seconds, release the power button, keep holding home button until your device recognises it is in Recovery Mode. (Perhaps 10-20 seconds.) If the device screen is black (blank) then it is in DFU Mode.
See this link and note the sentence commencing, 'If you restore from a different computer.... ' down near the bottom of the page.
I tried what you suggest, but de ipad has same issue. The ipad isn´t into itunes, and windows don´t recognizes.
I tried in another PC, and ipad appears but ask me to restore, i check "yes" and then Itunes becomes to download.
At 60 minutes, it was a problem, itunes stop download.
It is possible that my first PC has a conflict with usb port? and my second PC has problem with Internet conexion?
Tanks in advance
See iOS: How to update your iPhone, iPad, or iPod touch
If you are currently running an iOS lower than 5.0, connect to your computer & click on the "Update your device using iTunes".
Tip - Disable your firewall and anitvirus software temporarily. Then download and install the iOS update. After you update to iOS 5.x, the next update can be installed via wifi (i.e., not connected to your computer).
Where have you been backing up to prior to your present difficulty? If it is not on the other PC that you have tried you will have to set it up as a new device on that PC and then switch back to the normal PC and do a Restore from the latest back up there (or from the I-cloud I you have been backing up there).
As for the device not being recognised in your normal computer -
Firstly, make sure that your device is not hidden (left hand pane). If it just reads device then toggle between SHOW and HIDE.
Secondly, try all the other ports on your computer, even a number of times.
Thirdly, if you have another computer try plugging your device into it without taking any action, give it a moment, remove it and try it back in your other computer again.
If you need further help on restoring from a previous backup just come back here!
Texas Mac Max, I can´t try what you suggest, becouse the don´t run. Thanks.
alanfromnewtonards, you are rigth, my prior present dificulty is mi normal PC, insn´t the second PC.
I did the actions into the reference http://support.apple.com/kb/TS1538 , and ... surprise, finally the ipad showed in itunes.
All rigth, itunes asked my to restore ipad, i chek acept, and become to updtae software ...
But, after two hours, the progress bar didn´t grow, and windows shows windows with information about "a new harware found" and it can´t recongnize. And itunes shows window error "unknow error -1635 ...."
I closed itunes, and when i run again, it didn´t recognize ipad.
Conclusion: I am in the same point that yesterday, ¡I don´t belive it!
The good news is that i cat reproduces de issue. The bad news is that i isn´t at home, i am in holidays and i haven´t good internet conection.
Any idea? Please ...
Tanks in advance
A number of things! Your post title relates to upgrading yet you state that you have iOS 5.1.1 which is the latest!
Have you a fairly recent backup on your computer back home with which you normally sync?
Was that combination working OK before you went on holiday? Will you be back home soon? Can you wait until then and have the benefit of a better Internet connection and try the whole process over again from there?