Try the following.
Close Paint Shop Pro and any other programs.
Double click My Computer, then choose Tools > Folder Options
Click the File Ttypes tab.
Scroll through the list to find the file type in question, for example,
try looking for .jpg or .jpeg image.
Click the file type.
You should see a repair button.
If you do, click the repair button, then click ok to exit these windows. Try Paint Shop Pro file associations again.
If you do not have the repair button, then do the following.
Click the Advanced button.
On this next dialog, click work open, then choose edit.
Edit the field that says Application used to perform action to read like
the following line.
"C:\Program Files\Jasc Software Inc\Paint Shop Pro 7\psp.exe" "/dde"
If your version of Paint Shop Pro is located in a different area
than the default location in the listed path, then edit the path to
point to your version of Paint Shop Pro.
Click OK and exit these windows.
Try Paint Shop Pro again. You may need to repeat this procedure for each file type in question.