Can I install SQL Server 2005 Express Edition on the same server where I already have SQL Server 2000 Enterprise Edition?

Doing this also includes replacing .Net Framework 1.1 with 2.0, could that cause any disturbances to the already existing SQL Server 2000 ?

(None of these two databases are heavy production databases)

I don't know about the Server software, although I believe reading a Microsoft document stating that you can do that, but as far as the .Net framework is considered - 2.0 is not an upgrade to 1.1, it is a rightful departure from it, and thus they will coexist very peacefully on the same computer. I'd search the Microsoft knowledge base about SQL Server 2000 and 2005 Express, there should be something authoritative about it there. I, too would be curious to find out how it actually works.
Kamen

You can definitely run SQL 2000 and SQL 2005 on the same machine, but any one machine can only have one default (un-named) instance. As long as at least one of the two uses a named instance (which Express uses by default), you'll be fine.

-PatP

So, having 2000 and 2005 in parallel is no more dramatic than having multiple 2000 instances then, in summary?

And, I saw some web page where someone said SP4 should be installed before installing SQL Server 2005. I'm not
sure if they meant SP4 of Windows or SP4 of SQL Server, though. Any ideas?

Technically SQL Server 2000 sp3a is required in order to install SQL 2005, but as long as the machine has less than 4 Gb of total RAM I really prefer to apply SQL 2000 sp4 and SQL 2005 sp1.

-PatP

Eh... do you really mean "less than 4Gb", not "at least 4Gb" ?