Your post is lacking in details. It sounds as though your homepage has
been hijacked. Since you didn't give any specific information about what
you did, follow the general virus/malware removal steps below.

Go through these general malware removal steps systematically -
http://www.elephantboycomputers.com/page2.html#Removing_Malware

Include scanning with David Lipman's Multi_AV and follow instructions to
do all scans in Safe Mode.

http://www.elephantboycomputers.com/page2.html#Multi-AV - instructions
http://pcdid.com/Multi_AV.htm - download

You can also check to see if there are targeted removal steps for your
malware here:
Bleeping Computer removal how-to's -
http://www.bleepingcomputer.com/forums/forum55.html

When all else fails, run HijackThis and post your log in one of the
specialty forums listed at the first link above (not here, please).

Standard caveat: If the procedures look too complex - and there is no
shame in admitting this isn't your cup of tea - take the machine to a
professional computer repair shop (not your local version of
BigComputerStore/GeekSquad). Please be aware that not all local shops
are skilled at removing malware and even if they are, your computer may
be so infested that Windows will need to be clean-installed. Have all
your data backed up before you take the machine into a shop.

Malke

4 Days ago, I had the same problem when one of student download something
from the internet and allow the spyware to hijack my homepage. I tried this:

http://www.download.com/3000-8022_4-10743107.html

It took 1/2 hour to find and clean this spyware.

Hope this help, let us know!