Quote from gus1gus2000:
Strong suggestion, Do not have Norton Antivirus on your trading machine. I had the same plus many more conflicts (especially if running multiple monitors) Not to mention it uses about 1/3 of your resources. If you need an antivirus then go with the much less demanding Mcafee which will work just as fine. Your problem and many others which come from Norton updates is actually very common. Good luck
Interesting. I've had Norton for 5 years and this is my first such problem. Maybe I've just been fortunate. (Also, the same updated did not impact my Win2000 computer, only the XP.)