Ok got an iMac although my MacBook Pro has done this to me as well in the past and I'm pretty sure I was running Snow Leopard and XP in VMWare on them both. Now both are Lion, Parallels and XP. In Simpl when you go to type on a symbol's line both the enter keys stop functioning along with some other ones that make it a real PITA to work, I think a reboot fixes it but it will start acting up again. I ran across a fix that was stupid easy and should have bookmarked it, I think it had to do with Caps lock or something that the press got registered but the release didn't and something get's it corrected and synced up again but I have forgot what. It may have had something to do with Multi Monitor as well, got 2 extra displays attached to the iMac figured it might be useful info to throw in. If anyone knows the fix for this, please remind me or if more info is needed let me know.
Thanks
Jason
