Question : Problem: Can I reformat one of the hard drives that make up my Raid?

Experts, I need help urgently.

I have a Windows 2003 Standard Edition Server with a RAID made up of four internal ATA Hard Drives.

Yesterday, there was a power outage and when opening certain folders, we get a message saying "The file or directory is corrupted and unreadable."

I opened up Window's Disk Management and there is a yellow exclamation sign on Disk3. However, Disk0, Disk1 and Disk2 do not have this exclamation sign.

Additionally,  on the top window of Disk Management, the status of the drive says "At Risk".

I have clicked on "Reactivate Disk" but this yellow exclamation sign keeps appearing along with  ("At Risk") under the drive's status.

1) How do I recover the corrupted or unreadable files?
2) How do I figure out what type of raid it is: 0, 1, 5?
3) Do I need to buy the same hard drive size 120Gb or will it work with other sizes?
4) If I have to buy the same hard drive size, because they don't make them anymore, I was planning on taking out Disk3, reformat it with another system, then put it back.  Will this work?

Help!!!

I will give points to the person who can answer my 4 questions

Answer : Problem: Can I reformat one of the hard drives that make up my Raid?

1.  From backup!
2.  The drives are in a striped volume.....which means they are just grouped together for the sake of write speed.  If you were in a RAID 5 configuration, the files wouldn't be damaged and you would still have access to them.  Unfortunately they are not.....so backup is your only option.
3.  You don't have to have the same sized drive....just the same size partition.  So you can buy a larger hard drive, create a partition the same size as the other drives and put them back in the striped volume.
4.  With that hard drive going out like it did, you will have to create that whole striped volume again.  Once you replace the disk.....recreate the volume and then do the restore from backup.