Installation problem with Internet Security 2012

I am currently using 360 however that is due to expire in the next 2 days so I have purchased a CD pack of Norton Internet Security 2012 and when I tried to install it on my laptop this evening I keep getting the error message stating that it is incompatible with my OS (which is Vista Home Premium...and as states on the package, is supposedly compatible...)

 

I looked in the tech support online and they suggested I update my Windows service pack, which I did and tried the install again however I am still getting the same error message.  Have used Norton on several occasions and never had this happen before.  Do I need to uninstall my 360 before I install the new product?  Am sure it's all been done automatically in the past.  My new product is for 3 devices and I also need to install on my netbook this week but haven't done so yet as not sure if I will need to return the pack.

 

Any thoughts/suggestions welcome.

 

Thanks

 

PS:  Am in the UK.