Does DSL mount the hard drive automatically? Does df -h show any of the partitions (/dev/hda or /dev/sda) mounted? If not, and you want to mount a Windows C: drive, you can do:
mount /dev/hda1 /mnt/windows
This assumes the Windows partition is the first partition of the first IDE hard drive (/dev/sda1 for SATA). It also assumes the partition is of a type Linux supports. Fat32 is supported; NTFS is not supported as well, and I'm not sure if DSL has added NTFS support yet.