When in the Options (on Windows 7x64), when checking "Start Bitcoin on windows system startup" and then hitting Apply. There's a slight locking up of the program, then the box becomes unchecked. I'm not sure it's actually doing anything. Hitting Ok instead of Apply, yields the same results, except the Options dialog disappears and the checkbox is still checked. When you re-open Options, the checkbox isn't checked anymore. Running as Administrator has no changes.