Don't know why this happened, but it may save you some pain.
Trying to login tonight, I was getting password error.
If I start up CounterStrike then browse servers and join, I get password error.
If I start up steam browse servers before running CS, and join from there it is fine.
And no I didn't have caps on, and yes I can type.
I used to get that problem but the other way rnd before opening cs, i never found out why it did it just one of those steams mysteries just add it too the many.