Remove all antivirus softwares immemadiately, having more than one antivirus in system will itself lead to many problems!
I prefer the following only !
Download & Install the following 3 freewares. It forms a free complete security suite for your system!
1. Avira Anvivir - http://www.free-av.com/en/download/index.html .
Avira is best & light solution for excellent overall system protection & internet security with real time updates, .
Well first a reply to Saran008. Your message is nothing more than a ploy to get someone to purchase software. I already have malwarebytes and free-av and it does NOT do the job that your message purports it to do. Nice try.
I did find a solution however.
First, it appears that MS has found a solution to its IE8 version that me and many others were having problems such as tabs not closing down properly and causing PCs to freeze.
Now MS has a IE8 for different OS so I uploaded IE8 specifically for XP. The problems that I got last year with IE8 are gone. Also gone are the DCAD popups.
I then deleted Firefox from my laptop and all my problems are solved.