Hard disk not detected

If you can help me i will be very greatfull to u......... I have a Seagate ST3160211AS Seagate Barracuda 7200.9 160 GB Hard drive and a Seagate ST340014A Seagate Barracuda 7200.7 40 GB Hard drive connected to my mercury motherboard.. When i log in to Windows XP and go to My Computer I can see the partitions on 160 GB hard drive but not the partitions on the 40 GB one.. It is detected in the device manager but it is not seen in my computer.. Can any1 please help me solve this proble.. I guess it has something to do with changing the RAID options...

The problem is that u have done partitions for 160 GB harddisk, so do all the partitions of 40 GB or less than that.