Lotus Notes 6.5.1 is not supported on Windows 7. In Windows Vista you could get Notes 6.5 to work if installed it in C:\Notes and gave the user full permissions to the folder.. Everything would work, except for Instant Messaging. This technique no longer works in Windows 7. The first supported client for Windows 7 is Lotus Notes 8.5.1 Fixpack 1. If even u get success to install any how, it creates problem later. U can also check with Microsoft Compatibility Center for confidence. One way u may try, to install it under Compatibility Mode. For this purpose, u have to require to install the compatibility tools for Windows XP or Vista under Windows 7.
For single user installation with supported version, please visit <a href=”http://notes.unl.edu/newnotes2/installdocs/ln8std_install_pc.pdf”>Here</a>
Hope this helps u !