Blurred photos, jpeg photos with a big black block

I had recently put my photos onto my machine, think the machine is set up fine and working fine.

I transfered my photos from my sony camera to the pc, and they were all there clear and no problem as usual.
However i have noticed over the past week that the odd photo ( out of like 200 ) on one of my hard drive hve started to get like shaded black block half way accross them. Thought it doesnt show up on thumbnail, but when you open them its there.

Also on the hard drive my vista is installed on i transfered some photos to the desltop too, and the odd photo of those has also developed a block half way accross it.

Whats going on?

I remember i had this problem with some digital photos years ago, but they were old old photos that i had had for many years so just guessed they had become corrupted. but these photos i have only had on my pc a matter of weeks.

Athlon 64 4200
Asus A8N motherboard
2x 80gb Raid ( stripe 0 ) some photos on my vista partition which is on the raid array have become corrupted.
1x 320gb sata hard drive
1x 200gb sata hard drive ( some photos on here have become corrupted )
Geforce 6800GT
Neopower 480w
2gb Ram

Looks like your RAID stripe is causing the stripe. Download the (guess your running 32 bit) NForce/AMD drivers for V_-_A and update through the device manager.

Did you upgrade or do a clean install?

That is a strange problem -- also do not believe that raid striping is problem as this would corrupt other things as well ---- do the photo's have something in common ---- like time or format ---- or does this happen randomly --- to any photo.