I have an Acer Aspire. I loaded ESET NOD32 antivirus software from a thumb USB thing that I got at the store. As soon as that finished, my machine locked and I cannot do a thing with it. The machine has XP Service Pack 3. The only way I can turn it off is by holding down the power button. When it comes up it lets me choose the user and then it sits on the desktop with the cursor unable to do a thing. Any ideas of how I can unlock the machine and get the software off?