If you are currently using more than one partition then this might help you if you put programs in something other than your default installation/download C Drive.

1) Click Start
2) Click Run (Type: regedit)
3) Find HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
4) Find ProgramFilesDir
5) Right Click
6) Click Modify
5) Then edit it to whichever drive you wish to change it to.

Now all your downloaded files are going to download to that file you specified. Have fun, star if it helped.

Note: Always back up your registry before editing it to prevent any data loss or confusion.