Two days ago I discovered a virus on my system and tried to remove it. Yesterday I noticed that my external raid 5 drive appears as "raw" in disk management :

and when I try to access the drive through explorer I get a message saying the drive needs formatting:


Motherboard is an Asus Crosshair IV Extreme with the latest bios (if that's relevant)
The strtech drive has 4x1.5 TB drives in Raid 5 and I'm using eSata to connect it to my computer.
I'm running 64 bit windows 7 ultimate
when I boot my computer the raid drive is listed as healthy in the post screens.
The Capacity seems right in Disk Management (4191.53GB - RAW Healthy (primary partition) and the drive letter is the same as it was before
I'm pretty sure it was formatted using GPT filesystem as it's such a large drive and I think windows 7 forced me to use that.
I haven't tried to reformat it or anything but I did have to reinstall the JMicron Sata controller after the virus infection.
Write Caching is enabled (well it is now but I'm not sure if It was before)
Better performance (default) is set under policies, again I'm not sure if this was the case before though.
The driver is listed as eSata-2ExternalRAID SCSI DIsk Device by microsoft version 6.1.7600.16385
I don't have access to another drive of similar capacity and as a student I can't really afford to buy one.
I'm running testdisk at the moment, so far after about two hours it's completed about 1%.. and some of the messages its come up with so far are:

Please can someone tell me if its possible to rebuild the GPT table so that I can access the files once more and if so... how?
Thanks in advance.