Why you want to make that change?
The first answer is that you can’t.
--
Damián
I want to use an SQL Server because the data I have and the handling of that data is complicated and too complex for MySQL.
MySQL differs from SQL in many areas.
What would it require to make Magento compatible with an SQL Server?
I can’t understand why we’re talking about some holy war of technologies.
You post some information about Mysql 4 and SqlServer 2000. Both products are old versions.
Please, read about Mysql 5.0 and the latest vesrion, 5.1.
Second, there isn’t any techonologie better than one, it depends about your request.
And finally: do you want to use Magento?. Magento runs on Mysql.