virus.........can't log on to windows xp

hi folks,

i just got an email on my other computer.......it looked like regular spam, so i went to highlight it in order to delete it........as soon as i clicked on it the email opened up saying something about winning money or something similar...i went to x out of it but it wouldn't let me close it and another similar email opened........tried closing it also and it wouldn't let me........tried to open task manager.......wouldn't let me.........went to my start button in order to try and shut down the computer.......as soon as i touched the start button instead of giving me options the computer just shuts down on it's own and does a restart...........everything looks normal starting up until it gets to my windows log on screen.......you can see things flashing in the background like "ghosts" like something else is going on........my username is there but faintly and the space for the password doesn't let me put my cursor there........there is also the letters "EN" to the left which i don't think i have seen before...........anyways, to me it seems like a fake log on screen and maybe someone is trying to steal my password or something......basically i can't logon to my computer and it seems to be infected by a virus that was opened by the email...........i'm not sure how to get onto my computer to try and fix things.......maybe someone could help me get on in safe mode or something or has some other ideas.............any help would be great

thanks,
miles

 

p.s. after i click the mouse a few times while the log on screen is open it tells me i have to put in the correct username and password to log on......i click "ok" and the the log on screen seems back to normal with the flashing cursor where password line is........i'm just not sure if i should take the chance and put my password in or not in case my computer is hijacked

 

i was able to log on.....i changed my password just in case......ran some anti-virus tools and everything seems ok.......thank you for your time