Okay, got a bit further. Firstly, run msconfig and check the Startup tab. If it's listed, uncheck it. Also check the Startup folder (essentially the same thing, but sometimes the results are different) via the All Programs menu and delete it if it's listed.
If neither of the above apply, then you'll need to make a little registry hack. More info if/when I have it.
click here This advice from MS itself refers to the System32 folder, which is traditionally the most common version of this anomaly (it goes way back to NT and has been cropping up ever since!). This should still apply in your case, as you are looking for null values. As with all such things, it's not 101% guaranteed to cure the problem, but there's a good chance that it will.
WARNING: Back up the registry before you fiddle with it! I would have no worries about reg editing - I have to do so now and again - but please be careful.
Firstly, backup the registry by creating your own System Restore point, then change the empty value to 0 and see if that fixes it. If that does not cure it, try the advice in the MSKB link that I gave you - this is more destructive as it involves deleting strings, but may work. There are numerous variations of this anomaly, so it is difficult to pin down an exact solution.