Why don’t the accounts show up on the welcome screen on xp anymore?

I had a friend work on my pc, and it worked for a while after. I had an account with no password. Then I restarted my pc one day and now when the welcome screen comes up it is completely blank. There are no accounts or icons at all. I hit Ctrl-Alt-Del twice and tried to use my account name but no luck. I tried Safe Mode and all of the basics as well. HELP!!!