Quicken home and business 2001: Says to close quick tabs

Quicken normally does a save any time you close it. If you lost part of a file you had open, close it and open the last known good file and reenter your information that is missing.

If you have a bootable CD or DVD drive in your computer, download a copy of Hiren's BootCD, or Parted Magic, and boot to that operating system. Then you could copy the files off to another drive such as a flash drive or external hard drive.

uninstall quicken and then reinstall it putting in key code while doing it.
https://www.quicken.com/support/how-do-i-uninstall-quicken-windows
if it won't uninstall
https://www.quicken.com/support/using-qcleanui-uninstall-quicken

I'm sure there is. Except. Ditch Quicken. DITCH WINDOWS anything. Used-to-be programmers call Windows a 'Virus.' It is slow, and expensive. Learned from our whiz-kid son-in-law: switch to Linux. For home use, it is free, open-ware, which means Anyone can add 'fixes,' improvements. There is a business version, also.
Point is - no one writes viruses and mal-ware for Linux! So, you get to ditch paying for software to protect you from all that. I used Quicken when the kids were in public school. Mom gave them money, used them at tax time, until - their brain fried at tax time. Early 90's.
Next, Any software package you use or need is available on Linux, as a clone. Exactly the same. If needed for a business, likely at a lower price, since Geeks and Nerds write them, for fun! Heck, I did it for EDS in the late '70's, on mainframe IBM's, and later at NM banks. Very pre-home computers. Would do it still, just cuz I knew 3 or 4 languages, had my favorites, and just had Fun programming whatever was needed. Et Voila: Linux!

Look here on how to change passwords

http://quicken.intuit.com/support/articles/data-file-management/password/5288.html

I've this didn't helped, contact Quicken.

You cannot do this on the normal account register, as you might have done in earlier versions of Quicken. You have to use two special registers, by creating a BUSINESS BILLS and a CUSTOMER INVOICES register. To do this tap the CREATE NEW ACCOUNT button, in the MY FINANCES screen, and select these registers from the dialogue box. When you receive a payment from a customer, open the CUSTOMER INVOICES register. Then... 1. Tap the TYPE box, and choose INVOICE from the drop down list. This will enter INVC into the box. 2. Look at the button under the BALANCE column. Instead of the usual SPLIT button, this is now labelled FORM. Click on this, and a Customer Invoice Form will appear. Fill in the details from the invoice you have received. Under AMOUNT enter the amount received, less VAT. In the V column, enter the symbol for the appropriate VAT RATE, and Quicken will calculate and enter the VAT amount. 3. When you have completed all the required boxes on the form, click the SAVE AND DONE button, and The form will close. 4. You will see that Quicken has entered the details in the correct Registers. I 5. When you produce your VAT REPORT your item will appear with its details in the correct places. The process for entering a payment is similar, but you will then be using the Business Bills register. Problem solved ! John Cunliffe

Buy a different software. Maybe then Quicken will fix this software problem.

I just bought Quicken 2011. I tried all the proposed fixes and none have worked. If I don't find a solution soon, I will have to buy a product that works.

the only thing that might help is to create a restore point and restore you computer to a date earlier than when you lost your data

Check intiut's website. There have been some problems with 64-bit Windows Vista. You didn't specify whether you have 32-bit or 64-bit operating system.