Windows login doesnt work?

1

hi when i boot up my pc it comes to the user screen i pick my name and then type my password okay thats fine it works and all. but once im on my comptuer if i leave it inactive it will logout after 20 minutes and the screen will turn off. okay thats good but the bad part is when i try to login it says bad password… yet its the right password. and i makesure caps and all that crap is off soo i have noo idea whats up with this? then i end up rebooting and then logining in that way and its kinda anoying