It works fine on the Mac three possibilities
the preferences are corrupt trash the settings folder
the keyboard key is stuck but since it works in PS it would be highly unlikely
it doesn't work on Windows 7
Two more could be a conflict usually happens with conflicts with Entourage or other Microsoft software needing to updated.
Finally you are delusional and everything is working fine!
If you need instructions on resetting or moving the settings folder jacob will be around soon he has a link to a page on his site describing the method.
Sounds quite specific. Are you per chance using a tablet perhaps? Do you observe any odd switching in your Windows theme when launching AI?