Misspelled password

[Douglas Pollard]

  HI All,  I think I may have misspelled my password in Ubuntu. I set it 
up too open the first time work on the first Opening with out a password 
entry Works fine. But every time I want to make a video or do some other 
task I have to shut down Ubuntu and start over Because I can't put the 
password in.  I have been using Ubuntu  and for a while Linux mint. The 
computer came with windows 10. I installed Ubuntu I think fro a thumb 
drive. It installed beside windows on the same solid state drive.   I 
now have to restart the computer to pick either Ubuntu or Windows 11.  I 
think I have Ubuntu 21.1 installed but will check to see  let you know 
if you need the info. I am getting really long in the tooth at 88 years 
old so if you can keep any replies as none technical as possible that 
should help me understand,  I am using a Dell cxsH2g3 computer and it 
won't let me reinstall Ubuntu. If I could do that I could just reinstall 
and put in the right password. I would really like to remve Windows 11 
and change my password in Ubuntu If tht is possible???    Thanks, Doug