Есть вот такое заклинание от микрософта :

Manually start setup:

X:\SETUP\ACMSETUP.EXE /T VS98Ent.STF /S X:\ /n "" /o "" /k "YYYYYYYYYY" /b1
X=cd drive letter and YYYYYYYYY=cd key.

If you receive the following message "You must first run the Installation
Wizard"
Update the Registry using a .reg file (copy paste the below text into a
notepad file and name it with .reg) with the following then rerun the above
command:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\6.0]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\6.0\Setup]
"VsCommonDir"="C:\\Program Files\\Microsoft Visual Studio\\Common"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\6.0\Setup\Visual Studio
98]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\6.0\Setup\Visual Studio
98\SetupWizard]
"aspo"=dword:38395356
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\6.0\Setup\Visual Studio
98\SetupWizard-1033-ENT]
"heuristics"=hex:00,00,00,00,00,00,00,00

Должно помочь.
Если речь конечно идет об XP.