There was no need to re-post my original DELETED reply.
I had removed that post because I saw that you had actually complied with Pascal's suggestion to remove all the files.
It appears that the software used for this site is too dumb to recognize a simple deletion and must send a confirming email to you. I had indicated that "I changed my mind" but it still informed you of the contents of the post.\
On your problem:
If you have completely removed all traces of the program and all files (including the default template) and then reinstalled it, then my only other suggestion is that the program probably cannot find something.
Do you see a constantly "spinning wheel" Windows icon when you try to open WordPerfect? If so, it might be because it cannot find an installed printer (actually, a printer driver) to use. But this is just a guess.
For some other ideas see http://wptoolbox.com/tips/RepairDocs.html
-- and particularly the http://wptoolbox.com/tips/RepairDocs.html#misc section on that page. (E.g., it could be a corrupted Windows user profile).
On viewing hidden files and folders in Windows (from my notes):
Double-click My Computer [or just Computer in Windows Vista and Windows 7] and this starts Windows Explorer. On the menu for Windows Explorer, click on Tools. [Ed.: In later versions of Windows (Vista, Windows 7) you might need to press the Alt key to see the menu with the Tools option.] That gives you a drop-down menu of which the bottom entry is 'Folder Options'. Click on 'Folder Options'. This opens a dialog with 3 tabs across the top: General, View and File Types [in Windows Vista/7 the third item is Search]. Click on View. In this part of the dialog, there is a square central area with various items, each with a check box or a radio button.
Under the heading 'Hidden Files and Folders', click the radio button for "Show hidden files and folders" [or "Show hidden files, folders, and drives"]. Immediately under that option, de-select "Hide extensions for known file types" and also de-select "Hide protected operating and system files (Recommended)". Exit from that dialog.