virtualbox.org

As a host I'm running VirtualBox on Ubuntu 9.04. My virtual box version is:

Sun xVM VirtualBox Graphical User Interface 2.1.4_OSE

I created my WindowsXP image with 512M of RAM. Today I upgraded my host to have more RAM, so now I'd like to expand my Windows image to use 1G or 2G of RAM.

Can I change this in the Windows Guest? How?

You do this in the settings for the guest. It must be shut down (not in saved state)
If this is a 32 bit OS you can allocate up to 1.5 Gig if you have enough available.
VBox will allow you to use 50% of the available RAM (not the total) in the guest up to 1.5 gig.
Look in the log files of the guest and you can see how much available RAM VBox says you have.

Aha, I was in suspend mode so Settings was disabled!

This works great, thanks.

Great! I will mark this solved.