How do I activate my script when another program opens?

[micseydel]

To elaborate on heiner55's post - a level of indirection (a batch file) would be thes simplest solution. If you really want something more, and are willing to put the effort into it, you can look into things such as this. You might also want to checkout Gray Hat Python or its sequel for other information on how to achieve it. It's basically black magic so you're less likely to find something sufficiently cookie-cutter that it wouldn't be a decent chunk of effort.