Hi Kipp,
Go to Start/Run and type in:
msiexec /unregister [click ok]
Then Start/Run and type in:
msiexec /regserver [click ok]
The Windows Installer Service Could Not Be Accessed" Error Message When You
Add or Remove Program
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q315346
Another note is, if you are running DirectX 9, many users are having this
same issue. It seems to be prevelent to certain graphics cards and the
dxdiag tool, doesn't help.
The only workaround so far is to uninstall DirectX 9. If this is your case
and an option you are willing to try...
I have the download for the uninstaller listed on my site. The only
modification to be made is to extracte the zip file to C:\DXTEMP and
not C:\DXTEMP! as per the readme. Also, run it only in safe mode.
Uninstall DirectX 9 (Line 112)
http://www.kellys-korner-xp.com/xp_tweaks.htm
Registry Edits, Tips and Tricks for XP
http://www.kellys-korner-xp.com/xp_tweaks.htm