computer hangs before interrupt

HELLO,

when i start the comp, there is no problem , but after a few mins,i cant use mouse to do anything, as in the mouse cant be used to open windows from taskbar nor open other windows , that is i cant do anythin with mouse , it gives an impression as though it is hanged, but when i use “ctrl+alt+del” and just close it without doin anything then again comp is normal,

if i use alt+tab too its back to normal, but i want to use mouse till i switch off, how to fix the problem (i use xp, 256 ram , p4)

What is it that you are closing? Whatever you are alt+tabbing out of is using up your resources (which are already slim as I belive 256MB of ram is the minimum system requirements.)