Raid Issue

My father has a Dell XPS 400 and from his phone call the other day it sounds like one of the hard drives failed.  This happened a little over a year ago too but it was still under warranty so Dell replaced it.  I'm trying to help him fix it over the phone but I need more information then hes able to give me on how this works,  I'm guessing Dell set this up as a Raid 1 array but is also using Norton Ghost?

Below is the information he sent me.  Do I just need to replace the failed hard drive with another 160 gig hard drive and thats it?  Is there anything special that needs to be done?  How do I determine which drive failed.   (Please feel free to use tech terms and I'm pretty experience fixing computers).

Thanks

Intel(R) RAID Technology
Intel RAID Controller: Intel(R) 82801GR/GH SATA RAID Controller
Number of Serial ATA ports: 4
RAID Option ROM Version: 5.0.0.1032
Driver Version: 7.8.0.1012
RAID Plug-In Version: 7.8.0.1013
Language Resource Version of the RAID Plug-In: 7.8.0.1013
Create Volume Wizard Version: 7.8.0.1013
Language Resource Version of the Create Volume Wizard: 7.8.0.1013
Create Volume from Existing Hard Drive Wizard Version: 7.8.0.1013
Language Resource Version of the Create Volume from Existing Hard Drive Wizard: 7.8.0.1013
Modify Volume Wizard Version: 7.8.0.1013
Language Resource Version of the Modify Volume Wizard: 7.8.0.1013
Delete Volume Wizard Version: 7.8.0.1013
Language Resource Version of the Delete Volume Wizard: 7.8.0.1013
ISDI Library Version: 7.8.0.1013
Event Monitor User Notification Tool Version: 7.8.0.1013
Language Resource Version of the Event Monitor User Notification Tool: 7.8.0.1013
Event Monitor Version: 7.8.0.1013
Array_0000
Status: No active migration(s)
Hard Drive Write Cache Enabled: Yes
Size: 298 GB
Free Space: 0 GB
Number of Hard Drives: 2
Hard Drive Member 1: WDC WD1600JS-75NCB1
Hard Drive Member 2: WDC WD1600JS-75NCB3
Number of Volumes: 1
Volume Member 1: ARRAY
ARRAY
Status: Degraded
System Volume: Yes
Volume Write-Back Cache Enabled: No
RAID Level: RAID 1 (mirroring)
Size: 149 GB
Physical Sector Size: 512 Bytes
Logical Sector Size: 512 Bytes
Number of Hard Drives: 2
Hard Drive Member 1: WDC WD1600JS-75NCB1
Hard Drive Member 2: WDC WD1600JS-75NCB3
Parent Array: Array_0000
Hard Drive 0
Usage: Array member
Status: Normal
Device Port: 0
Device Port Location: Internal
Current Serial ATA Transfer Mode: Generation 2
Model: WDC WD1600JS-75NCB1
Serial Number: WD-WCANM1828372
Firmware: 10.02E01
Native Command Queuing Support: Yes
Hard Drive Write Cache Enabled: Yes
Size: 149 GB
Physical Sector Size: 512 Bytes
Logical Sector Size: 512 Bytes
Number of Volumes: 1
Volume Member 1: ARRAY
Parent Array: Array_0000
Hard Drive 1
Usage: Array member
Status: Failed
Device Port: 2
Device Port Location: Internal
Current Serial ATA Transfer Mode: Generation 2
Model: WDC WD1600JS-75NCB3
Serial Number: WD-WCANMH833628
Firmware: 10.02E04
Native Command Queuing Support: Yes
Hard Drive Write Cache Enabled: Yes
Size: 149 GB
Physical Sector Size: 512 Bytes
Logical Sector Size: 512 Bytes
Number of Volumes: 1
Volume Member 1: ARRAY
Parent Array: Array_0000