Can not get past the welcome screen

I don't even know how to begin this! This morning I woke up to a black screen
on my monitor that had in big letters WARNING: You have a trojan (and it said
another virus also but I can't remember its name). My McAfee was not
allowing me to run it, so I uninstalled it, reinstalled it, it did a quick
scan said everything was ok, but I still had the black warning on my monitor.
It said for me to run spyware, so I did, I downloaded Spybot, ran it and it
did find a lot of items. After I ran it, all warnings on my monitor went
away. I think I may have told it to do something with the registry and that
maybe my problem now. This is what happens:

1. I turn on the computer
2. It boots up to the welcome screen, where it shows my name (I did have my
husband on as another account user, I removed him from it when his computer
was fixed).
3. I click on my name to go to my desktop
4. It goes to my desktop, my desktop is there but it just sits there for a
few minutes
5. Then it goes back to the welcome screen
6. If I click on my name again at the welcome screen, my desktop appears
just for a brief second, then goes back to the welcome screen and says it is
logging me off.

Can you help? I must have really screwed up on something! I was thinking
about just reformatting in a few weeks, but now I can't even do that, I can't
get past the welcome screen!

Thank you for any help and suggestions! PS: I do not have a CD to reboot
with, none came with the computer, which is a HP.

Debbie
.

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