Unable To Def-rag System

I waited way too long between defrags on my daughter's computer and now when I go into defrag it, it just goes to 1% and stops. The system doesn't hang or freeze, the defragging process just never goes beyond 1%.Her system runs XP Pro 1.73 Ghz. Not sure if this matters but she also has Panda Titanium virus/spyware. I've disabled the Panda while running defrag and this did not make a difference. But I've checked for spyware using Spybot and Adaware as well. No spyware or viruses were found. I was just wondering if there was a program besides the defrag that comes with Microsoft to use to defrag the machine or a work around.