I have i pad 1. i have some questions regarding synchronizing. I usually download e books from my dropbox app on ipad and then i save in
ibooks...b'se its easy....but when i synch my ipad with itunes in my pc, it erase all of my ibooks that i got through dropbox or sometimes i saved from emails. and also it erase all changes i made in my music playist directly in ipad...b'se sometime if i don't like some songs so i delete in that or move to other album.. my all changes got deleted and i got whatever in i tunes.. could you help me in this, how can i keep all my stuff as it is what i didn't get it through itunes..

iTunes is notorious for deciding it is right, and what is on the iPad is wrong. It is usually safest to add everything to iTunes, even make your playlist changes there, then sync back to the iPad.

The other approach is to never sync with iTunes. I can't advise on that, since I do it the first way.

One thing that may work, or may not. First, go into iTunes Preferences, the Devices tab, and turn off auto-syncing. Then each time you connect the iPad, before you sync, right click on the iPad in iTunes and choose Transfer Purchases.