So my windows 8 pc started running real slow and was telling me that my pictures directory was invalid and that I had nothing in my pictures folder. I so then restarted the pc and it took forever for it to finally get to the login screen I would type the password as it took around 1-2 minutes per password character once it finally typed all the password i hit enter and it says the password is invalid. I have no way to login back into my pc and need some help. I tried booting in safe mode but it wont let me. I tried using F8 and shift-F8 both didn't do anything. any ideas or advice?

Please answer the following questions to help me understand the issue better:
Are you using the Microsoft Account or Local User account?
Are you using a 3rd party antivirus application on your computer?
Do you have any other user account on your computer?
If you are using the Microsoft Account, refer to the “Reset your password” section from the following, rest the password and check if that helps.
What to do if you forget your Windows password.
http://windows.microsoft.com/en-us/windows/what-do-forget-windows-password#1TC=windows-8