To download a trial version of RPE you need to determine if you have a 32 bit or 64 bit processor. Go to System in the control panel or start menu to determine which you have.
Compatible Operating Systems:
Windows Vista 32 or 64Bit
Windows 7 32 or 64Bit
Windows 8 32 or 64Bit (NOT compatible with Windows 8 RT)
Desktop PC – Intel Core 2 Duo 2.93 GHz Processor (or equivalent or faster)
Tablet PC – Atom 1.6 GHz Dual Core Processor (or equivalent or faster)
2GB of RAM (or greater)