Computer randomly restarting... again

hi, i posted on this forum about a week ago about my computer randomly restarting. u guys told me to check the ram with the memtest so i opened up my computer and cleaned all the dust off and ran memtest. there were no error or anything and the computer was fine after that.. but since yestaday the computer has been randomly restarting again... i ran the memtest and all was fine but the restarts are still happening

Attach 5 or 6 of your latest minidumps. To your original thread please.

Regards Howard :)