It seems that I have the Redirect Virus. Windows XP. Can someone please help?

When doing searches on Google and Bing when I click on a result of the search I get redirected to sites that others have described on this forum. I have also been getting messages that I have high memory issues. I have done a defrg and I have a lot of memory available. I'm using the latest version of Norton Internet Security and have done system scans and they have not helped. I did run NPE at the suggestion of the Norton support links before I found out about the forum and it didn't seem to help. I have Xp on the computer. I will follow all instructions to the letter if someone would be kind enough to help me. I'm not a master computer operator but can do most things with help. Thanks In Advance, Greg