Advice Nedeed ? System Troubleshooting

I am using windows xp and my system is infected with some sort of virus actually I really don?t know whether it is a virus or what . I am running avast antivirus and also have avg antivirus and avg anti spyware. I used both of them in safe mode and they only detect cookies which I deleted, but they just reappear every time I open internet explorer. I am having random pop ups, some contain viruses that my antivirus stops and I don?t think my antivirus is effective for all sort of virus. I am not sure what needs to be done so if I could get some help I would really appreciate it.