Can't update apps nor purchase new apps

Hi everyone, could someone help me? I've had my iPad now since last year August (2010). But just here recently, actually, yesterday, I changed my password for my Apple ID. Since than, I have not been able to make updates to the many apps I have on my iPad. I now can't even purchase a new app. I don't use a credit card to purchase, I use the iTunes gift cards. My address is the same and yet, just since changing the password, I can't update. Does anyone have any suggestions or solutions. thank you.

Change the password back to the old one comes to mind first. Secondary, on the iPad log out from the AppStore and log back on, do the same thing on iTunes and sync your iPad...

Let me know how it works out! :)

I agree, last time my account was messing up for no real reason, I logged out, then back in, Viola!

:)Thanks everyone for your help. I think I've just discovered why I'm not able to download or update. I checked my billing address, and I find an error in the information. Now how this has happened I don't know, because I haven't been in there to change anything. Got me thinking, someone may have tried to hack my computer it seems but weren't successful. Right on Apple computers!!!! Now I've just got to make sure the address I had in there is right and try again. Also, I can't remember who, thanks for the info of how to download upgrades in iTunes, I found it. Peace and love all!!!