Using WinXP/SP2, 2.0 patch, 3.0.4 co8 patch... I honestly can't figure it out, anyone have any ideas?
I'm at work so to open the console it is either hold shift and ~ or it is hold shift and space. If that does not work for you then I'm not sure what to tell you.
It could be a US/UK keyboard layout clash. Try SHIFT and the key above the TAB (¬). You need to hold the keys down for a second or two, as well.
For me, it always works on the second try with Shift plus Tilda, but never at first attempt. So, maybe it's the same for others?