You have to install SQL 2005 as a named instance.

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>I'm attempting to install SQL2005 Developer Edition on my primary (workstation) box, which also has SQL2000 Developer Edition SP4 installed on it. I'm installing the new version into its own folder, but for some reason, the 2005 install REFUSES to install separately without UPGRADING the previous Database Services installation (and, thereby, rendering SQL2000 useless). I've tried it three times, and each time I have to completely reinstall my 2000 version after attempting to do this.
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>I do *not* want to upgrade. I want to have a **COMPLETELY SEPARATE INSTANCE** of SQL2005, with a separate Database Services installation, so that I can use them BOTH. I can't believe that this type of installation is unusual, and I can't understand why it's not working.
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>What foolishly simple thing am I doing wrong?
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>TIA,