No restore button in iTunes

So you haven't got a backup on that machine but you expect a backup option ?

Backup to what state ?

You need a Hard reset to get back to factory options - not a backup.

When you do that, your phone will be like when it came out of the box for the first time - nothing wil be left on it - no contacts, no emails, no music, no aps - nothing.

If you want to do that, then its General-->Reset--->Content and kep it plugged in to the mains all the time. It may take a few hours.

Right click the phone in the left device pane, select restore.

wjosten wrote:
Right click the phone in the left device pane, select restore.

The OP has never used this computer with this iPhone - will that still work ?

Yes, he can restore as new. You can restore a phone as new on any computer.