I am not an Expert by any means , but It seems that any virus software you have installed in XP that protects any part of the operating system will not allow a good upgrade . I dont know if removing it will change anything. the problem is ,,,, this is an Observation now ,,, the changes in the operating system are widespread and massive , it makes XP almost like Vista. But not quite. however , My hard drive failed in My Old 1.6HP laptop and I installed Xp then upgraded to SP3 It now works fantastically . the Old virus and protection software will noit work I went to something New and better . The old software antivirus that is when it was upgraded to SP3 did not protect my computer . It also prevented a Complete installation of SP3. Which Left my Macine Vulnerable . Hope this Helps .learned by Doing. :rolleyes: :-D