to check available ram and cpu use
type: "ksysguard" into the run command dialogue box
you should get something like:

- sysmon1.png (52.23 KiB) Viewed 1651 times
this is in a 256M virtual box with parameters similar to your unit to give you an idea - thanks, i would never have tried such a low ram spec.
this

- sysmon2.png (64.29 KiB) Viewed 1651 times
is the unit running the virtual box
in both units top graph is cpu usage.
as you can see in the sysmon1 image the cpu is running at 100% for a lot of the time.
however at times it gets to less than 40% and ram useage is about constant about 100Meg
if your cpu useage is 100% all of time and ram is not fully utilised the usual suspect is the graphics card / driver setting.
i hope this is of help