Can I run 2010 and 2003 side by side?

[Jennifer]

Can I install Visio 2010 on a machine that already has 2003 installed and run both versions at the same time?

[Surrogate]

No (without use virtual machine), some times ago on my PC was installed 2003 and 2007.
for example last time i worked in 2003, this version mean as default. When i started 2007, system upgraded (popup form with progressbar) and 2007 became as default !