Canon EOS350D Protection Errors

Hi,
I am having problems with my Canon EOS350D.
I have been taking a series of pictures with it over the last few weeks and everything was fine; the pictures took great, they deleted properly and I could upload them properly to my PC.
Then I changed the resolution of the pictures I was taking from the smallest resolution to a larger resolution and from then on have had problems. I really can't see that changing the resolution has caused the problems, but maybe it is just a co-incidence.
Anyway the first problem I noticed was when I came to upload the pictures to my PC. I upload them either through a card reader or directly from my camera through a USB lead. Either way, it was not reading the CF card and the pictures could not be loaded to my PC; it was saying the drive was corrupted or the camera could not be read.
I then tried to delete the pictures on my camera and it was saying they were protected (even though I had not protected them). I followed the instructions in the manual to unprotect the pictures but it then said the images were unreadable.
I then changed my CF card and took more pictures (back at the lower resolution) but the same thing happened. They too could not be uploaded to the PC and could not be deleted from the camera as it was saying they were protected.
I then re-formatted both my CF cards and wiped them clean.
I have tried talking more pictures with both cards but still when I try to upload them it is saying the drive is corrupted or the camera is unreadable. Sometimes the pictures can be deleted from the camera, sometimes it says they are protected.
I am baffled! For me to have the same problem with two CF cards and also two methods of uploading the pictures to my PC indicates to me it is neither the cards nor the PC uploading method which is at fault, hence, process of elimination leads me to think it must be something wrong with the camera itself (though how it just suddenly starts protecting and corrupting images when it has been working fine for several years with the same CF cards, I am not sure….?!)
Note, I use SanDisk CF cards.
Any advice would be greatly appreciated.
Many thanks

Hi,
In addition to my previous thread, I am now getting Err 02 when I try to take pics with either of my SanDisk flash cards (which trabsalets to CF card error). The camera appears to take the pic but then says Err 02 and there is no pic image.
Ahhhhhhh!!!!

Try reformatting the cards in the computer. Also try connecting the camera or reader with a different USB cable.

Also try to leave a line between paragraphs. It's a struggle to read as it is

You may want to check for a bent or broken card pin in the camera.....I doubt it would be the card considering you tried two, but it may be worth it to try one more just in case you did something to both cards that could've damaged them (maybe your computer corrupted them when you formatted them?...I don't even know if that's possible but you never know). If all else fails....off to Canon. Good luck

BTW....welcome to the forum