Jennifer......Hummmmmmmm it sound like you may have a virus or a hijacker .......I would suspect sasser .......If you go to Symantec site ...and D/l the sasser removal tool ....save it to disk .......then with the infected p/c offline ........run the removal tool and it should get rid of it ......
http://securityresponse.symantec.com/avcenter/venc/data/w32.sasser.b.worm.htmlDo you have Ad-Aware on your infected P/C .......if so again do not connect to internet and run Ad-aware .....
let us know how you make out
any error messages or anything running ....look in your task manager and see if you see anything that looks odd.
dl65