problem with iPhone

I expect I am going to sound totally thick here, but...

my startup files got corrupted and I had to get my PC cleaned (?): this meant I had to reinstall iTunes as well as othr files. I then reloaded mypre-existing iTunes library from a hard drive. Since then, whenever I have tried to download new music the system keeps saying my Apple account is disabled for security reasons. I have tried renewing it but system will not accept any uodate or renewal going through email account reset or reset via questions. I how now uninstalled iTunes. Any ideas as I am going increasingly mad here. Help please!!

Try going into iTunes and re-authorizing your computer. I suspect whenever it was "cleaned" that it's no longer being recognized by Apple. You can do that from the main menu "Store". I believe it's the same on a PC as on a Mac (which I'm using). If that doesn't work, you may have to contact Apple customer service.