Microsoft Net Framework 1.1 Service Pack 1 64-bit Download [work]
no official 64-bit version of the Microsoft .NET Framework 1.1. Because it was developed before 64-bit computing became standard for consumer PCs, it is natively a 32-bit (x86) application.
Note on Terminology & Availability:
Microsoft never released a native 64-bit version of .NET Framework 1.1. Version 1.1 was designed exclusively for 32-bit (x86) systems. While it can run on 64-bit Windows via the WOW64 (Windows 32-bit on Windows 64-bit) compatibility layer, there is no standalone "64-bit" installer. The following post explains how to handle this correctly. microsoft net framework 1.1 service pack 1 64-bit download