Originally Posted by CoolDaddy78
The tilde key [~] problem is usually linked to a device driver
called eHome MCIR and / or ENE Infared Transmitter /Reciever. This has mainly been seen on systems that have Windows Media Centre installed and have a Microsoft looking remote control (kinda like a dvd player remote) for use within the media centre. Basically the driver of the remote re-assigns several keyboard functions however within windows you shouldn't really notice this an example would be that opening notepad you'd still be able to enter the tilde [~] key.
To clarify if this is the problem you need to open device manager either type 'device manager' in the vista start menu or get to it any other way that you see fit and expand the keyboard section and human interface devices. if you have any of the above within the list simply right click them and uninstall them. You should then be able to open the console within Oblivion.
A work around for the eHome driver is to click update and manually change the driver to "HID-compliant device" this should end the problem without needing to uninstall the device all the time. I've not tested this method personally as I don't really mind uninstalling the device.
Let me know if this fixes the problem for you.