At random times and, honestly, quite infrequently. What usually happens is the computer starts to slow down. I, then, usually delete all the TEMP files and clean out the recycle bin and a few other diddies and reboot. Then, all is well. A actual crash may occur 3 or 4 times a year... maybe. A lot of it depends on what Lil Stash has downloaded or what games he may have played and what buttons Mrs. Stash has accidently said, "Yes" to. But, we all have a cross to bear.
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"Always go to other people's funerals, otherwise they won't go to yours." - Yogi Berra