ZBrushCentral

Re-installing 4R8 on the same windows computer

Hi
For some reason my pre-process current command stopped working.
Same basic files I use over the years to sculpt.
After I sculpt the file no matter what I sculpt pre-process just keeps analyzing until I interrupt it.
Does anyone has any idea why it suddenly started to happen?
If not what are the steps to re-install 4R8 on the same computer?
I do keep an original download file.
Thanks
Is this the right forum to post?