Help with Dll please

Hi all:
I have one problem with a Dll.
I have the same Dll in two versions. One older than the other.
Depending on the SO i have to register one or the other.
How can i do it? The InstallLib can do it?

Can you help me please?

PD: I know how to detect the SO but not how to register one or the other because both have the same name and changing it wont work...

Use logiclib e.g.

Call GetWindowsVersion

 Pop $R0

 ${If} $R0 == 'XP'

 !insertmacro InstallLib REGDLL NOTSHARED REBOOT_NOTPROTECTED XP_dllname.dll $SYSDIR\dllname.dll $SYSDIR

 ${ElseIf} $R0 == '2000'

 !insertmacro InstallLib REGDLL NOTSHARED REBOOT_NOTPROTECTED 2000_dllname.dll $SYSDIR\dllname.dll $SYSDIR

 ${EndIf}

I see what you meant by SO now, you meant OS as in Operating System?

You can use that code, or even better:
!include LogicLib.nsh
!include WinVer.nsh
...
${If} ${AtleastWin2000}
...
${Else}
...
${EndIf}

Stu

Im going to try it now.
Thanks !!!