Windows XP Professional, have to add .exe

I have never before had to consult a forum with a Windows-related problem, but here goes:

In my XP console, I all of a sudden have to add the file extension to applications I wish to run, including, but not limited to, ipconfig, ping, net and other "built-in" components. If I don't, all I get is a "is not recognized..." error.

Has anyone else had this problem? How did you solve it? And no, I don't believe in re-installing XP, which many seem to think is the correct way of solving problems with Windows :).

I'd be _very_ happy if anyone knows about what's causing this problem. It's not a big problem, but being used to not having to include the .ext when launching apps, I constantly forget and have to try again. Which is a waste of time. :)

--- palpha

The cause of this problem is an invalid entry in the HKEY_CLASSES_ROOT\ exefile\ shell\ open\ command Registry key. The correct data for the (Default) value should be "%1" %*

In fact, my HKEY_CLASSES_ROOT\exefile\shell\open\command (Default) is "%1" %* ... But it was a good idea. Does this registry entry really affect the cmd.exe command line behavior?

Anyway, I'll have a look through my registry, but would be very happy to receive further suggestions as to what is the root of the evil in my system... ;)