If you are unable to type into the data entry screen scroll to the top of the form. You should see a check box that says Don't Show Preview Window.  Check it.

Remove data protection from the operating system:

No-execute and execute protection are all names for DEP. This process feature increases security, but may cause problems with certain programs.

Several OSs have no-execute or execute protection. Microsoft has added this as well in SP2 with data execution prevention (DEP). This precents code execution in memory regions already marked as storage. This is a powerful tool against buffer overrun exploits.

If a program is failing and you want to disable DEP to see if that is the cause. Here are the steps. (Just disable DEP for the program in question… don’t disable it for your whole system.)

1. Click Start
2. Select Control Panel
3. Select System
4. Click the Advanced tab
5. In the Performance region select Settings
6. Click the Data Execute tab in the dialog box that opens
7. Select Turn on DEP for all programs and services except for those I select
8. Click Add.
9. The open dialog box will open. Browse and select your application.
10. Click Open
11. Click Apply
12. Click Ok
13. Reboot

"That 32-bit editions of Windows Vista are limited to 4GB is not because of any physical or technical constraint on 32-bit operating systems. The 32-bit editions of Windows Vista all contain code for using physical memory above 4GB. Microsoft just doesn’t license you to use that code."

Full story: http://www.geoffchappell.com/viewer.htm?doc=notes/windows/license/memory.htm