The Montego series of sound cards are not supported in Win 2K or Win XP.
The following instructions are offered on an "AS IS" basis, as a courtesy 
to our customers.
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1. Make sure the card is not sharing IRQs. Make sure the card is installed in 
   an unshared PCI slot. This is sometimes PCI slot 2, but consult the
   computer or motherboard manufacturer to be sure.  

2. To check for IRQ sharing, open the Device Manager. In Windows 2000/XP, 
   right-click on My Computer, click on Properties, click on the Hardware tab,
   then click on Device Manager.  
   
3. Click on VIEW and select Resources by Type.  Click the + next to Interrupt
   Request (IRQ).  This will show all of the IRQs in use in Win 2000/XP. 
   Remember the card will be listed as an Aureal Vortex card not a Turtle
   Beach Montego II.

4. Make sure the card is not on IRQ 9 or sharing with any other device except
   IRQ Holder for PCI Steering.  If it is sharing or on IRQ 9, uninstall,
   move the card to an unshared PCI slot, and reinstall.

5. If Windows 2000/XP is forcing everything to share no matter what PCI slot
   the sound card is in, then ACPI is installed.

6. The Advanced Configuration and Power Interface (ACPI) is the latest power-
   saving innovation, and it is supported by Win2000/XP. It lets the 
   operating system assign system resources to hardware and handle shutting  
   unused hardware down, "hibernating" the computer, and so on.

7. If you run Win2000/XP on an ACPI machine, it'll try to share as many 
   interrupt requests (IRQs) as it can. There's sense to this; making every
   device that can share an IRQ do so means you get the maximum number of
   free IRQs, for any hardware that has to have an interrupt to itself.
   Servers that are packed with gear are much easier to configure, this way.
   Unfortunately, the downside of this feature is that you get Interrupts
   sharing on many computers, with lots of IRQs standing idle.

8. So basically, if you have W2000/XP and ACPI with most of your devices
   sharing an IRQ, such as your TB soundcard, you should disable ACPI in
   the BIOS(check with motherboard or computer manufacturer), and reinstall
   W2000/XP selecting the "repair" option.

9. Fortunately, Win2000/XP can install on top of itself, and not trample
   your existing applications, just like Win98. You just select the "repair"
   option, and tell the installer to repair your old install of the OS.


IN SUMMARY:
   All you need to do to install this card is install it in an unshared 
   PCI slot and boot up. Windows XP will automatically install the correct
   drivers.


See also the article:
"Win 2k / XP - ACPI and IRQ Resource Conflicts"

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