I won't be able to bank 2007, even though I didn't get into it until after July 31??
First of all, as others have said, Disney sometimes waives banking deadlines on newly acquired points. But just in case they don't and to illustrate how banking deadlines work, let's assume they don't waive them...
Between Feb 1 and July 31 2007, you can bank up to 160 of your 2007 points. For whatever reason, let's assume you close tomorrow and decide to bank 50 of the points.
After the 6 month 100% banking window, there is a 3 month 50% banking window. So between August 1 and October 31, you can bank points up to a cumulative 80 points. Since you've already banked 50, you can back up to 30 more points. Had you banked more than 80 during the 100% window, you couldn't bank any more the rest of the year. Let's assume you bank 10 more points on September 15th.
After the 6-month 100% window and the 3-month 50% window, there is a 1-month 25% window. Since you've already banked more than 40 2007 points, you can't use the 25% window. But if you hadn't banked any of your 2007 points, you could back up to 40 from November 1 - November 30.
In the last two months of your use year, you can't back any of the points. So, come December, you've banked 60 points and have 100 that must be used by January 31, 2008 or they will expire. In addition, the 60 points you banked must be used sometime between Feb 1 2008 and January 31 2009. If you don't use them by then, they expire.
On Feb 1 2008 you get 160 new points. The banking windows on those are independent of anything you have done before.