BleepingComputer.com: can't install anything

I have searched the forums here and googled high and low for an answer to this wretched problem.Invalid E drive 1327/exit code 1603.
I first noticed the problem when I tried to install Office 2007 the msg was something to do with windows installer.I followed instructions to correct this
(by dos commands)and eventually installed office 2007.
Also unable to open pdf files attached in my yahoo account but I guess that's another thread.
Now I want to install a printer and I'm getting the same message of an invalid E drive ;the error report said return code 1603,also D:\setup\hpzmsiol.exe which makes no sense to me.I've looked in the registry and can't find anything with an E drive attached to it.
Could someone please post some very simple answers;including where to put spaces if I have to use dos commands.I have checked the shell folders and there are no Es there either.
Thank you