Duplicate post, same as posted in the General Hardware section. See my suggestion in your other post.  It's not a "Dell" issue.  It's how you set up the accounts.
Currently I have my Power save options set to "never" for both the display and sleep mode. I have one admin. account and 4 standard accounts set up. When I'm at the Log In screen that shows the accounts, if the space bar is pressed, Windows automatically logs in to the first listed standard account (upper left on my display), which does not require a password. This was a problem when I tried to use the Power Options; I previously had them set to both turn off the display and go to sleep after 30 minutes. So even if I was logged in to admin. account when the computer went to sleep, when I hit the space bar to wake it up, it would automatically log in to the first standard account. It did this no matter which user was active when the computer went to sleep, it would log in to the first account shown. I contacted Dell about this and their solution is to uninstall Windows and re-install it. I don't really want to do that since it took me 3 days to get all the accounts set up and personalized and I have since added tons of files I would have to back up. I would also have to reinstall all the programs I've installed. I would like to use the power saving feature, but if that is what I have to do to make it work, it's just too much trouble to go to. Everything else seems to be working fine. Is this a common  or known issue? Any ideas how to fix it other than uninstall/reinstall Windows 7? Thanks.
Log In / Power Save problem - Inspiron 620 Windows 7