SP2-won't Shutdown Always Has Iexplorer.exe

for quite awhile now both my computers but they seem to work pretty good although alittle slow. but when you go to shut them down, both of them a box comes up and says ending program where you can wait for it to end the program or you can click on end now. well it doesn't matter which you do most of the time the computer won't shut down. it just keeps going back to the end program box. It is always this program--iexplore.exe always that one. One time I looked into the task manager and it had like 5 or 6 of the iexplore.exe in the application part. anyway it is getting quite annoying. I ran asquared when this was happening and it caught what it said was a trojan (didn't write it down) I deleted it and it seemed to work for awhile. But now it is back to the same ole thing. Can someone enlighten me on what might be wrong? It is on both of my computers.