Hi and welcome to JustAnswer:
You can and should file your 2010 and 2011 tax returns. You will have to mail your returns as the period allowed for electronic filing has expired. I have provided links below to the IRS Form 1040 and instructions for 2010. Additional forms and years are available if necessary. I have also provided a link to the IRS web page where additional forms are available.
If you owe tax there is a late filing penalty and a late payment penalty. If you have a refund due there is no penalty charged.