Hi there, and welcome to the VDC! It's safer here ;) I hope you can fix your problem with the Source SDK no launching.
In the meantime, don't forget to sign your posts on talk pages! Also, when submitting a post remember to use the Show preview button before the Save page button, so you can preview your text and make further corrections to it (if needed). This way you will prevent "flooding" the Recent Changes page with lots of little edits. :)