[donaldjeo]

I think you have a hardware combination that Vegas doesn't like.
If I were in your shoes I think I would pull one of the Xeon chips out and see if you can get Vegas to run on just one chip.
As I have never had a dual processor machine I don't quite know how you would re-do the OS to run on just one. A BIOS setup?
I know that on the Single Zeon or Pent Pro you could disable/disable the multi-processor through hardware manager.

You haven't given much info as to error codes. Are there any bodies in the Event Log? Check system and application log. (Rt click My Computer | Manage | event logs.
And, what happens when you try to run Vegas ? Crash PC (BSOD)hang, shows nothing?
Go into Task Mgt (CTRL-ALT-DEL) Processes and click the CPU to see is anything Vegas like is running.
Are there any warning errors in H/W Mgr?

What happens if you try using a different sound card?
You need to try to do stuff that will make something different happen.