My previous post on Backup Compression reminded me to post about installing the latest SQL Server 2008 CTP (here’s a link to the download page).

I’ve installed SQL Server 2008 many times, both within Microsoft and since leaving in August, but I’ve never done it on a system that has SQL Server 2000 installed too. Last week I decided to create a VPC image with a few instances of SQL Server 2008 on as well as SQL Server 2005 – basically updating the VPC image from the Always-On DVD that contains all the Hands-On Labs that Kimberly’s written over the last few years for SQL Server 2005.

One thing I’d heard is that SQL Server 2008 won’t install side-by-side yet with SQL Server 2000, or any SQL Server 2000 tools. I’m not sure whether this will be the case at RTM, but it’s fair enough for a pre-RTM CTP. So, I tried it and sure-enough it failed. I then used Add/Remove Programs to de-install SQL Server 2000 and thought this would do the trick. Nope – the install still failed, thinking I had one or more SQL Server 2000 instances in the VPC. Next I tried deleting the 2000-specific directories from the C:/Program Files/Microsoft SQL Server directory. Nope – the install still failed. Finally, I fired up regedt32.exe and deleted the 2000-specific registry keys. Then the install finally worked.

So – to save you a bunch of time figuring this out, using Add/Remove Programs doesn’t de-install SQL Server 2000 well enough to satisfy the SQL Server 2008 CTP setup.