I understand you're looking for Visual Studio 2008, but I need to provide an important clarification before offering guidance.
It has been discontinued and replaced by newer versions (VS 2010, 2012, 2013, 2015, 2017, 2019, 2022). Microsoft’s free offering today is Visual Studio Community (2022), which is feature-rich and supports legacy frameworks up to a point. Download Visual Studio 2008 Free Full Version