It's because you have windows installed on the old drive. Most likely you are using a diff profile name on the newly installed Windows on the new drive, so that profile does not have access to the profile on the old drive. I suggest opening the PC, disconnect the new drive, make the old drive master, boot the PC. Partition the old drive to make a D:\, move all the crap you want to that partition. Make it slave again, plug in new drive, boot to that Windows, now you should have a C: D: E:, most likely all the crap you moved to the newly created partition will be on E:. Move it to C: and it's all on the new drive. Sounds complicated maybe, but easy to do. Or just get a copy of ERD Commander and move the shet!