First, XP64 is not a recommended OS for CS4 by Adobe.
The Cineform files are very high bitrate and require fast hard drives. The size of your hard drives may indicate they are older/slower IDE drives, not SATA. I assume your Cineform files are on the 500 GB drive which may be badly fragmented and/or over 75% full which can slow things down further.
Suggest adding another 1 TB SATA drive.