VIRUS (BYMER WORM)

i’ve recently set up my computer as an in home network with my room mates computer…instantly we bothed recieved the bymer worm..we have tried everything to get ride of it …it just keeps coming back…we’ve tried avp..norton….f-secure…other virus progs….deleting manually by going into registry etc…can anyone help us get it out ….we have setup bodetect and blackice but i fear its a little to late for those now..from what i’ve read once you have it installing a virus program after the fact is useless…PLEASE HELP!!!