how can I transfer files from disk D to disk C?
You cannot transfer applications from D: to C: (you'll need to uninstall them, then re-install them on C:) You can transfer your own files from D: to C: by using either drag-and-drop with both windows open side by side, or cut-and-paste from one drive to the other.
Are this individual disks or partitions on the same disk? Reason I ask is that Win7 has a facility to change partition sizes. Always pop back and let us know the outcome - thanks
Most likely, because this is a laptop, the D: partition is your restore partition, yes some laptops don't hide the restore partition and people just try to save stuff there. So, if you have saved anything there, I would move what ever you want off the D partition to your documents. Now go to your recycle bin, right click, properties, turn off the recycle on the D: drive.
Next Go to your disk management and right click on the D: partition, change the drive letter, and set it to blank.
Done
