adware.agent.bn and " NET FRAMEWORK" problems

 my laptop(xp  home sp2) injected trojan.dowloader

                        & adware.agent.bn

so I use spyhunter & spyware doctor to kill them .   It show ".......clean competely"  but I dont think so,5 hours later,the  adware.agent.bn appear again.

ps. I cant work with the safe mode  to kill virus

moreover, after that I can't open any website with IE .   It appear sth wrong with ".....NET FRAMEWORK"

please help me !!!!!!    thanks a million!!!!!!!!