How to get in?

I bought an Acer netbook from the classifieds that originally had Windows XP but since has been reformatted with Linux. I don't have a username or password, nor do I have a disk drive to get things going. Is it possible to reset everything for a fresh start???

I wopuld suggest going back to the seller and ask them what the root password is so that you have access and can configure it.
What version of linux is installed? That would help us help you too.

I received the root password and Ubuntu I guess is the name you're looking for. Sorry for the ignorance, it's been Windows since 1996 for me

Have you tried to start the system, since you received it and did it ask you to create a user account?

Did the person you purchased the Acer from format the drive and install Ubuntu? Or did you? It seems from your post that you did not do the install. If you have Ubuntu, are you able to boot the machine as asked above and if so, what exactly happens?

The person before me installed the Ubuntu. I was able to get in initially, but after deleting a user name to "make it my own", I thought there would be a guest login (similar to that of windows). I was wrong. It doesn't recognize the user name or password anymore and I'm out of options. When I power the machine on, it boots as normal and i get to a "username" and "password" screen. Like I said, it no longer recognizes it and I cannot progress any further.

did he give you the user name "root" or was it something else?

Have a look at https://wiki.ubuntu.com/RecoveryMode and then Add a User on Ubuntu Server - How-To Geek