Norton Speed Disk 2GB HDD 25 Hours ???

Hi,
I have a pc that got a virus. It got the w32.elkern.4926
w32.klez.h@mm
w32.nimda.a@mm(dll)
w32.nimda.a@mm(dr)
The hard drive filled to capacity and slowed down to a crawl. The customer tried to remove some files and programs to free up space before I got it but no luck. He tried defrag and it would not work. I cleaned the virus and got the system to boot but when I run Norton Speed Disk it has taken 25 hours to complete 50%.
Any fixes that you know about. I did run some HDD test with Microscope and the HDD passed.
Thanks