i'm having a problem on my HP Database Server, here is the error:the device \device\scsi\acc1, did not respond within the timeout period

I have RAID 5 (4 Disks), i belive there is one hard drive failing. How can i check it?
Is there a software (beside the RAID firmware) that i can run on windows 2003 server to do a RAID check up ??

Best Regards.