Windows 7: I can't get in my account

I was installing a patch so i could get the Personalization Panel on my Windows 7 Home Edition and had to restart my computer. When i was logging in my user account i typed my password and the screen just went black and then just brought me back to the start up screen where you pick a user. I share a computer with my sister and she couldn't log in her account either. I'm guessing there was probably some kind of virus or something but i'm not sure. What can i do?

Hello Dendz, and welcome to Seven Forums.

If you had system protection turned on, then you could see if doing a system restore at boot using a restore point dated before you installed the patch may be able to undo and fix this for you.

Hope this helps,
Shawn