man i have to question you,please answer.
1.-¿what page you download that file or whatelse?
2.-¿Your antivirus detected something like troyans or viruses?
3.-¿can you type something in internet explorer or in a document?
the possibles answer are.
you got a virus or a troyan
you got infected and when you get this problem for a long time you can not repair it.
¿solution?!
you have to reinstall your computer or your OS.
Please answer.