I also agree that we can only recommend you CONTACT ACER.
I find it ODD that you were able to login before but now you can't.
Are you referring to a BIOS password (to prevent BIOS changes) or the Windows login password?
BTW, if your Acer is out of Warranty you may be out of luck. My brother-in-law had a bad hard drive so he needed to contact Acer to get a copy of Windows.
Guess what they said?
We can't give you, or even SELL you the discs because your Warranty is expired.
When I tried to contact them later I could only find a page that told me to put in the SERVICE NUMBER to contact Customer Support but it would only work if the Warranty was still good.
(I contacted HP a year after my dad's Warranty was up and they sent me backup discs. I did this in case the hard drive died. Everyone should have an IMAGE or way to reinstall Windows that's separate from the physical hard drive in the laptop.)