I took a job offer and they did a background check and inform me that I have a warrant, I cant start job until I take care of issue. I have a week

You need to hire an attorney to find out what the warrant is for, and then research how serious the warrant is.  If it is for a failure to appear for a traffic ticket and just a fine, for example, you can go to court and clear it up on your own.  If it is for something more serious, you should have an attorney do the research for you and make arrangements regarding court - you don't want to end up in custody.  Feel free to call with any questions or to speak about it further.  Paul Geller (213) 627-2144.