Может, из-за SP4?

ERROR LOG

[08/06/03,11:03:01] setup.exe: ISetupComponent::Pre/Post/Install() failed in ISetupManager::InstallManagerHelper()
[08/06/03,11:03:01] setup.exe: Component error string not specified in ISetupManager::AddToActionResultCollection()

Конец из setup log

...
[08/06/03,11:03:04] vs70uimgr: Entering RunningComponent() method.
[08/06/03,11:03:04] Setup.exe: ISetupManager::RunInstallFromList(IP_POSTINSTALL) completed
[08/06/03,11:03:04] Setup.exe: ISetupManager::RunInstallLists() completing
[08/06/03,11:03:07] vs70uimgr: Entering RunningComponent() method.
[08/06/03,11:03:07] VS70pgui: Failed to increment max steps for small progress. Logging as event not error ... noncritical.
[08/06/03,11:03:07] Setup.exe: IsRunningUnattended
[08/06/03,11:03:07] vs70uimgr: Entering DisplayFinal() method.
[08/06/03,11:03:07] Setup.exe: GetGlobalCustomProperty({710A502B-4669-405C-A985-BA21545509BA})
[08/06/03,11:03:07] vs70uimgr: ISetupManager::GetGlobalCustomProperty() failed to find global prop in CUIMgr::GetGlobalProperty()
[08/06/03,11:03:07] Setup.exe: GetGlobalCustomProperty({47EAF7DE-458C-4C05-B3E1-82B9C563679B})
[08/06/03,11:03:07] vs70uimgr: ISetupManager::GetGlobalCustomProperty() failed to find global prop in CUIMgr::GetGlobalProperty()
[08/06/03,11:03:07] vs70uimgr: Entering Next() method.
[08/06/03,11:03:07] VS70pgui: Entered CPageHeaderDynamic::OnShowWindow method
[08/06/03,11:03:07] Setup.exe: GetGlobalCustomProperty({710A502B-4669-405C-A985-BA21545509BA})
[08/06/03,11:03:07] VS70pgui: ISetupManager::GetGlobalCustomProperty() failed to find global prop in CFinishPage::GetGlobalProperty()
[08/06/03,11:03:07] Setup.exe: AddGlobalCustomProperty
[08/06/03,11:03:07] Setup.exe: GetGlobalCustomProperty({5245094D-36FD-4472-8161-FD6CF4E5EDAE})

Скопировал ошибку в яндекс и сразу нашел ответ: если в названии фирмы, на которую зарегистрирована винда, есть пробелы, то VS не установится. Заменил в реестре и всё стало ОК.

Кранты!