in case of hd spcae runnin slow, it might be a good idea not to let windows manage your swap file size. determine the size your self( "solid swap file") by setting the min and max same, like 512Mb or maybe 1024, depending on your needs. this way ur puter won't run out of swap (and crash) even if ur hd becomes full.
anyway best thing is to del some files or get a new hd.