My Mac OSX Randomly Exposes

Hi all,

Has anyone come across a case where by Mac OSX SL randomly exposes whilst working? It keeps sporadically happening to me! I've even tried getting a new hard drive and installing a fresh copy of Snow Leopard on that and it still happens! Plus, Shift+E doesn't work. :S

And in bootcamp mode with Windows 7 Ultimate 64-bit the shortcut volume, brightness, etc keys don't work and the weird thing is Shift+E doesn't work as well.

This has happened to me before and it was fixed when I applied Apple's EFI update. But has since returned and everything's updated and I don't know what to do! It's so annoying!

Any help would be appreciated.