b) backup, do a verify a rebuild and put backups (AGAIN) on external media for use on ANOTHER PC.
c) try installing a fresh copy of the program on ANOTHER pc to prove you can use the live DATA there
d) Ensure you did (a) thru (c) before even dreaming of doing (e)....... and that you have a FALLBACK position on another PC (your colleagues, your family's or your 'other PC - but DO OIT on another machine before (e)
e) and then consider the various Knowledgebase suggestions that imply that a UNinstall and Re-install may be required, and on that note take good heed of fellow Accredited Partner: Kevin's, highlighting of using Revo to do a proper uninstall (in some of the google solutions suggested.
f) Do not come back and ask for help about doing (e) unless you can prove you successfully ran your business on another PC for a few hours on (d)