Suggestion :-
For any future screen shots you can reduce the width of the treeSize display,
and if for any particular folder expansion you could place the C:\ display adjacent to the corresponding F:\ display and create one screen shot showing both displays,
that would allow me to see both C:\ and F:\ side by side in the same TAB on my browser.
C:\ has almost 11 GB extra data than F:\ in System Volume Information.
I suspect this is due to System Restore Points,
and if you restored your system to the earliest available Restore Point then in theory this will undo all the changes which it has monitored.
If and when you try that, stand by for a bumpy ride,
you might find you are worse of and then you could be thankful for a macrium image backup to restore the current state.
Under C:\from_old_computer you have 7697 MB,
This probably holds backups that could have been created when your computer first went bad,
or backups and "work-in-progress" when you were using "Vista Easy Transfer- program"
If you expand this we might get an idea of what it holds.
I will not have any clue about the relevance of or how to use that 7697 MB of data,
but I am sure there are experts around that can advise you.
Under "F:\Users" you have 14,207 MB
Under "C:\Users" you have 6431 MB
If you expand both of these by one level you will see the cause of the difference.
It is quite possible that F:\ is showing many user profiles, and C:\ is omitting some.
I know that as administrator on my XP Laptop I had full access to all system files and all my profile,
but no access at all to other user files -
EXCEPTING
a Macrium image backup ensures that every file in every profile is backed up,
and If I then mount the image backup as P:\ and tick the box "Enable Access to Restricted Folders",
then I could use TreeSize to fully explore P:\
Your Clone F:\ was created by Macrium to similarly include everything.
It might be worth mounting an image of C:\ as P:\ and running TreeSize on P:\
You might find more user profiles than you can observe direct on C:\
Under "F:\ProgramData\Microsoft" you have 202 MB
Under "C:\ProgramData\Microsoft" you have 836 MB
If you expand both of these by one level you should identify the cause of the 634 MB difference.
I understand that in theory a Flash Drive may have a Partition Table which could hold 4 primary partitions,
but that it cannot have an extended partition table to accommodate extra logical partitions.
In Practice Windows Disk management does not let me create more than one partition on a Flash Drive,
and a third party partition manager attempts to do this but with disappointing results.
I am fairly sure that when no disasters occur with Outlook or "Vista Easy Transfer- program",
you could Clone C:\ to F:\ and your one partition would be good,
but I fear that the MBR might be "distorted" due to Flash Drive technology limitations,
in which case cloning C:\ from F:\, or alternatively Image backup of F:\ restored back to C:\,
would give a good partition but the MBR might fail to boot up,
in which case you would need the WinPE Boot Rescue CD to implement "MBR Repair"
I think that exhausts my ability to advise on how to determine what is different between C:\ and F:\,
and how to make image backups that should allow an easy recovery to the existing state if anything else goes wrong.
I am unable to advise upon the relevance of the differences between C:\ and F:\ and what to do for Outlook etc.,
but there are experts around that can take it from here.
Regards
Alan