Hi.

It seems, that IE was hijacked.
Visit http://www.hijackthis.de (english page) and post the logfile there. In case he finds a virus, you'd better reinstall windows to ensure, that the system is not corrupted...
To avoid such errors the next time visit http://www.dingens.org and execute the program from there before doing ANY other internet activity after re-installing Windows (except of updating to SP2 from a trustworthy source). And use another browser ;-)

Regards MisterL