Does anybody have a hunch why one would occasionally, at unpredictable times, and for quite a while, get intensive jittering on a Toshiba Tecra notebook screen, with vertical lines and sometimes vertical bands appearing for fractions of a second, and the computer apparently reluctant to follow the keyboard or the mouse with usual promptness? When I reboot Windows XP, the problem is left behind, apparently, but I have most of my modern software under VISTA Business. Defragmenting (which I have scheduled once a month, and which is reported done on apparently the first occasion after the scheduled time as to be expected) is apparently not the reason, and it isn't nearly that disrupive either.
I could reload an old Acronis system dump of my VISTA system years ago from a CDd-ROM, I think, but I am not eager to deal with the technicalities of that, if I do not have a strong reason to expect less trouble along such a path.
Thanks for your attention.