setup cannot write to registry key

I have Vista service pack 1. Word 2007 as part of Office Home and Student
2007 began to have errors...e.g. it did not respond to the cursor and would
not open doc or docx files. Excel worked fine. I tried to reinstall Office
Home and Student from the CD I purchased: The install was unsuccessful
because:

1406 setup cannot write to registry key
\CLSID\{F0291081-E87C-4E07-97DA-A0A03761E586}
I was told to go to:
c:\Users\Dell\AppData\Local\Temp\Setup0000145c\PSS 1OR.CHN

I checked to see I was the administrator then removed account control,
spyware and error checking programs running in the backgrdound and shut down
Windows Live OneCare. No change. Office Diagnostics did not help. Several
System Restores did not help.

I don't know how to go to
c:\Users\Dell\AppData\Local\Temp\Setup0000145c\PSS 1OR.CHN

I think my registry needs to be tweaked to allow the write.

Can someone help me please?