and Kaspersky ought to be able to help you out of your fix -
http://support.kaspersky.com/faq/?qid=208285998

If that doesn't work for you (or if you want to try it first) you might try pressing the F8 key as the computer boots then try to start up in NORMAL mode under your regular account.

If you are able to log on using your regular account install Microsoft's TweakUI. after installing it run it and expand the Logon entry in the left window and select Autologon. UNCHECK the box that says Log on automatically at system startup.

Now you should be able to make use of the USERS applet in Control Panel to remove the account they added.