Cannot install VS2010 SP1 - visual-studio-2010

Question

I believe this falls under the "software tools" requirement. :)
I have tried to install VS2010 SP1 twice. Both times, it installed successfully, but when I open up VS2010, it still says RTMLDR.
I'm just trying to do this so I can install the WP 7.1 SDK, but when I try to do this after "installing" SP1, the SDK installer says that I need SP1.
I did some searching online, but have only found information regarding actually errors during the installation.
Here's the info in the dialog:
Microsoft Visual Studio 2010
Version 10.0.30319.341 RTMLDR
Microsoft .NET Framework
Version 4.0.30319 RTMLDR
Installed Version: Professional
Microsoft .NET Micro Framework v4.1 01018-587-3172636-70083
Microsoft .NET Micro Framework SDK v4.1
Version 4.1.2821.0
Microsoft Visual Basic 2010 01018-587-3172636-70083
Microsoft Visual Basic 2010
Microsoft Visual C# 2010 01018-587-3172636-70083
Microsoft Visual C# 2010
Microsoft Visual C++ 2010 01018-587-3172636-70083
Microsoft Visual C++ 2010
Microsoft Visual Studio 2010 Team Explorer 01018-587-3172636-70083
Microsoft Visual Studio 2010 Team Explorer
Add Reference Dialog Plus! 1.0
An significantly enhanced Add Reference dialog for managed code projects.
Crystal Reports Templates for Microsoft Visual Studio 2010
Crystal Reports Templates for Microsoft Visual Studio 2010
Hotfix for Microsoft Visual Studio 2010 Professional - ENU (KB2268081) KB2268081
This hotfix is for Microsoft Visual Studio 2010 Professional - ENU.
If you later install a more recent service pack, this hotfix will be uninstalled automatically.
For more information, visit http://support.microsoft.com/kb/2268081.
Hotfix for Microsoft Visual Studio 2010 Professional - ENU (KB2542054) KB2542054
This hotfix is for Microsoft Visual Studio 2010 Professional - ENU.
If you later install a more recent service pack, this hotfix will be uninstalled automatically.
For more information, visit http://support.microsoft.com/kb/2542054.
Indent Guides 11
Indent Guides
Adds visual guides at each indentation level.
PowerCommands for Visual Studio 2010 1.0
A set of power commands for Visual Studio 2010
Security Update for Microsoft Visual Studio 2010 Professional - ENU (KB2251489) KB2251489
This security update is for Microsoft Visual Studio 2010 Professional - ENU.
If you later install a more recent service pack, this security update will be uninstalled automatically.
For more information, visit http://support.microsoft.com/kb/2251489.
VSCommands 2010 3.8.0.6
Prevent accidental Drag & Drop in Solution Explorer, Group Items, Locate In Solution, Create Code Contract, Copy/Paste References and many many others!
Windows Installer XML Toolset 3.5
Windows Installer XML Toolset 3.5.2519.0
Copyright © Microsoft Corporation. All rights reserved.
I looked at Add/Remove programs and didn't actually see SP1 there.
I have disabled Indent Guides, PowerCommands, Productivity Power Tools, an VSCommands 2010, since I know I've updated to SP1 on another system that had .NETMF 4.1 and WiX. Then I reinstalled SP1 and it's still coming up as RTM. I looked for the KB numbers in "uninstall an update", and sure enough, they are not there.
I then uninstalled .NETMF 4.1 and WiX 3.5 and that didn't help either. I then did a repair on my VS2010 installation -- no luck. And now I've just uninstalled and reinstalled VS2010, and I still cannot get SP1 installed. Once again, no errors are reported after installation.
Has anyone else had this problem, and if so, how did you fix it?