I can't use special keystrokes, anymore.

When I want to input a special character (like, say, é), I'm told by Character Map to hold Alt and press '0, 2, 3, 3'. The problem comes from me getting an error-tone whenever I try doing that. I *used* to be able to pull special characters off like that, but it doesn't work anymore. What do I do?

Well it sounds to me like you either need to find a way to get your keystrokes working, or else find another way to input characters quickly

It's not a matter of quickness, as the system seems to disapprove of my pressing anything while I'm holding Alt. The largest point of my curiosity is that I was not too long ago able to do this.

Just use a real keyboard layout. I have a é key.

Just download Autohotkey and create your own hotkey to input special characters.

OK seriously, I think if you hold any key down for 5 seconds it will show a popup window that asks if you want to turn it on or off, but it might be something else, I forget

@6: It's called sticky keys.  I imagine if you have them enabled it might fuck things up.  Just hold the 5 for 5 seconds to have the option of disabling or enabling it.