Thank you Kewlx25 and arges86 for your support. You both deserve *****.
I used Partition Commander 11 (32-bit since 64-bit has issues) to clean two SATA disks of partitions and for formating. Then, I installed XP Pro SP3 (32-bit, full version installation disk) on one SATA and Win7 (64-bit, full version installation disk) on the second SATA. DVD/CD drive in BIOS was ahead of the SATA. One SATA was restricted with X in BIOS. Both systems work fine. Win7 seems to be running better than VISTA. Laptop has Intel XEON processor (seen with 4 processors in Device Manager), 3GHz.