Installating DEFAULT instance of SQL Server 2008 R2 Express Edition with Advanced Services on a Windows 7 64bit with AMD Phenom(tm) II X4 945 Processor failed with error:
Rule Check Result
Rule “Same architecture installation” failed.
The CPU architecture of installing feature(s) is different than the instance specified. To continue, add features to this instance with the same architecture.
Uninstallation of DEFAULT instance of SQL Server 2005 64-bit Developer edition was not clean and I was able to see instance MSSQLSERVER mapped to MSSQL.2 in the registry. After cleaning up the registry, rule “Same architecture installation” succeeded.