Well,this is 2 months old
but may offer a clue, especially if you do not update this PC right away. You may want to check Windows Update history.
Since you are operating the rudimentary Vista Basic on a 2Gb PC I assume it is a netbook, this is max. RAM and the boot drive is very small. Since cleaning out the temp files, etc. produced a 'cure' you might want to check your boot drive space.
If Vista and especially Basic offers an Action Center you might want to look at your Reliability Monitor's (if you have that) timeline.