Diskeeper Defragmentation

Hello all, I am new here. Hopefully will get my answer shortly.

I am getting a somewhat strange behavior from Diskeeper 2008. When I try manual defragmentation, it does so very quickly for my C: drive. But for all other drives, it is a shit. It seems that I’ll have to wait forever to let it complete.

My sys info:
Intel Celeron processor,
128 + 256 MB RAM,
40 + 80 GB HDDs

Thanks,
Yasir