Sorry for your loss. When did your spouse pass? Do you have a child?
You can file a Joint return the year your spouse died. For the next two years following a husband's or wife's death, the surviving spouse can file as a qualifying widow or widower if they have a qualifying child. That basically lets you continue to use the same tax brackets that apply to married-filing-jointly returns. After the year of death if you don't have a child you file as Single.
Then to file Single you should start over and set up a new account for yourself and not transfer from last year. You will have to re enter any prior carryovers and depreciation, etc. manually.
