Log in/ log out

Hello,
I see where some of you are coming from
when u say u log in, and then it logs right back out
I, too, am having this issue.. apparently because of
a virus I may have picked up. blablabla
Man, what I don't get is simply this... how can u type
anything in anywhere if u can't type anything in anywhere?
I can only get to my log in screen and nothing else
I can't type whatever anywhere??!
I have an install disk Windows Xp
got it from a dude who get it from a dude
has the little number things u gotta put in and all
that..yea that's a'' good
but I can't run it if I can't get to my desktop
i tried the boot order thing and that ain't doin shit
I mean unless I am totally stupid, which my in fact
be when it comes to this whole damn thing.
I am at my wits end! HELP,MAn
btw I am on a different computer obviously
dont ask me how i am writing this
seems to be one of many dumb things ppl say
BewilderedBex