Vista fast user switching disappeared

My fast user switching option in Vista Home machine suddenly disappeared. I remember it was there, then it was not. I don't know why this happened, but here is how to fix it.

A rough translation:

Run regexit.exe
Go to HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows > CurrentVersion > Policies > System
Look for a key named HideFastUserSwitching. If it exists, change it's value to 0 (zero). If it does not exist create it as a DWORD and set it to zero.
You might need to log off before the change takes effect.

"The system cannot execute the specified program" Error

You are trying to run some program on Windows (such as apache.exe or htpasswd.exe) and you are getting "The system cannot execute the specified program" error. This usually means that the program you are trying to run was compiled against DLLs that are not on your system. You should use Dependency Walker to see which DLLs are missing, and then install them.

The Apache 2.x binary windows distribution, specifically, was compiled against the Visual Studio 2005 re-distributable package, which you can download from microsoft.

Further reading (1) and (2)

Edit (Nov 2011):
Following this comment (by Annonymous) please note that you may need to download and use the 2008 package and not the 2005 one: The official download for the Microsoft Visual C++ 2008 SP1 Redistributable Package (x86) or The official download for the Microsoft Visual C++ 2008 Redistributable Package (x64)

Does GDS slows my hard disk?

I've a encountred a strange problems that when Google Desktop Search is running on my PC (which it almost always is), my hard disk's read speed is about 1/6th of the normal speed. I'll contact google to see if this is a known issue. I'm using several HD benchmark tools to test the speed, most notably Simpli Software's Hd Tach.

Here are screenshots of my disk's speed with and without GDS running.