32 bit CAD software

I have 3D CAD software that I ran on my laptop when it was 32bit.
Now I have converted to 64bit I can no longer install the software.
I was told I can tell Windows 7 to recognise the software as 32bit?
I am not dure this is true.
How can I install it on my 64bit laptop now?
Is there a way?

I do not have maintenance anymore so I cannot get the software as 64bit.

When you were 32 bit was it also W7 or something else such as Vista or XP?

Generally most 32 bit software will also run under 64 bit but 16 bit software which can run on 32 bit will not run on native 64 bit, so are you sure it isn't 16 bit software?

What is the name and version of your software; have you checked the compatibility center to see if your software is supported?

Have you tried installing in compatibility mode?

By any chance do you have W7 Professional, Ultimate, or Enterprise so you can run Virtual PC - XP Mode?

I was running XP 32 bit
It is Solid Edge V20
I haven't tried to install using compatibility mode.
I had never heard of it before.
I wouldn't have a clue where to find it!

According to the compatibility center Siemens SolidEdge works fine in 64-bit.

How do you install it? From a DVD?

Make sure you are logged on as an administrator. Put in the DVD and when autorun starts simply close it. Open windows explorer to the DVD-Rom drive and find the executable. Right-click on the exe and select Run as an administrator from the menu choices.
(BTW this is NOT compatibility mode this is just merely making sure it is installed with administrator access rights)

And you never said which version of W7 64-bit you have, Home Premium, Professional, Ultimate, ???