If you have a blank entry in MSCONFIG it is likely to be as a result of one of two things:

(1) A program install/uninstall has not completed properly and therefore not updated the registry "Run" keys. Looking at these registry keys may in some cases reveal an entry with a Name but no Data, others may have neither:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run
HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce
HKCU\Software\Microsoft\Windows\CurrentVersion\Run
HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce

Check these keys and see if there's an entry under Name and it may give a clue. As no program isn't being loaded in the Data column then the registry entry can safely be deleted. It's recommended that you read an article such as the Windows Guide Network one before modifying the registry.

(2) Disabling an entry in MSCONFIG hasn't updated the resgitry properly. If you check the registry keys you can often find one with a valid "Name" but no "Data"

(3) A virus or other maliscious piece of software has compromised the system. Many virusses modify various registry keys, including the "Run" keys.

This suggestion comes directly from an MS tech support person and they recommend you contact MS directly. Before doing so, make sure any virus scanners you have are using up-to-date virus definitions and perform a full system scan of all files.

(Note: HKLM refers to HKEY_LOCAL_MACHINE and HKCU refers to HKEY_CURRENT_USER)