first, I too own an L745 and have had similar keyboard problems. I am pretty disturbed bout how Toshiba is not addressing this problem.
No brainer problems like this in Windows is the reason that I changed over to Mac two years ago for 99% of my computing. I mean REALLY... if you cant fix your keypboards, you're worthless.
That said, here's a partial fix that restored my use of the bad latters tht were screwing up.
Goto Control Panel/Keyboard and set your SPEED slider to the LEFT completely. Hit APPLY.
Somehow this restored my bad keys 99%.
Still problematic but now I am less inclined to toss the laptop out through my window!
good luck!