Microsoft will tell you it's less than this, but their estimation is based on running just XP, with no other software in the background. To run it properly with anti-virus, and anti-spyware software, you will need at least 512MB of RAM, but preferably a full GB.
In addition, I would recommend no less than a 1.4GHz CPU in a laptop, and no less than a 1.8 GHz CPU in a desktop. Pentium 4 equivalent, or higher.
Also, I would recommend the CPU have a full 1MB L2 cache, versus a 512KB L2 cache if possible.
Stop and ask when you don't understand the "Geek"...

