Software install problem

[Rob-Dog]

Hi all,
I am new to this forum as you can see. However I'm hoping that someone out there may be able to help me with my problem.

I am running Win XP on a 2.5Ghz P4 with 512 Ram & a Geoforce4 MX440 graphics card (if that info helps).

I am trying to install the Eidos game "Shellshock Nam '67" however when I ran install, initially, it asked me to uninstall the "Sims Deluxe Edition" (which is made by EA Games). After a bit of messing about trying to getover my problem & getting nowhere I uninstalled the sims, deleted all files and references to it, ran Norton windoctor so that it would remove any remaining references to sims files & tried to install shellshock again. This time it came up trying to install the sims.
I find this most strange and very irritating.
Has anybody got any ideas why this is happening and/or how I can fix it?