Can't open encrypted files after reinstalling boot image

I had to reinstall my C drive image from Acronis True Image 8 the other day, and since that time I've been unable to open encrypted files on my D drive. I use Windows XP Pro and I've only used the attributes setting on the file itself to do the encryption. If I select the file, open the properties page, and then look at the advanced attribute settings around encryption, I can see that I'm supposed to be able to open the file transparently -- but I can't, and I'm wondering if my security certificate settings changed as a consequence of reinstalling the C drive image. I have not myself changed any security certificate information since I created the image -- though I did set the encryption attribute on those files since the time I created the image -- but I'm wondering if that got changed as a result of reinstalling the image.

Any tips for getting that encrypted file open would also be helpful....

Thanks.

Mark A R Mitchell