If you do get the taskbar icon showing then try this:
Open MFME, wait for it to be visible on the taskbar.
Click on the MFME taskbar icon.
Then press ALT and SPACE together, a small window will pop up, click on the Maximise option.
Alternatively try the Move option and hold down either left or right arrow keys and see if it comes into view.
If this fails then try this:
Open Regedit
Navigate to [HKEY_CURRENT_USER\SOFTWARE\CJW]
In that key you will see an MFME key. Just right click on it and chose delete.
If this fails, then try this:
Navigate to the location of the MFME.exe, normally this is C:\Program Files\MFME or maybe C:\Program Files (x86)\MFME.
In this location you will find a separate executable called Update.exe.
Try double clicking on this file and it should open a small update window.
If not, then this could be the issue.
In that case try renaming Update.exe to Update.old.
Then re-try loading MFME.
If none of this works then I am out of ideas for now sorry.