KB000436: What are the Steps to Re-install the MS ChemStation? - MS ChemStation 

If you are re-installing the MS ChemStation software to correct a problem that has developed, the first attempt would usually be to install over the existing program, following the instructions in the MS ChemStation User's Guide (G1034C) or in the MS ChemStation Installation Guide (G1701AA/BA/CA). If this fails to correct the problem, you can re-install as above, after backing up your data and methods, deleting the [PCS] sections of WIN.INI and deleting or renaming the HPCHEM directory. Details for these proceedures are included in the document below.