Error - Isdone.dll Crc Check

I’d seen isdone.dll errors before. Usually a bad download. Corrupted archive. Wrong password. Annoying, but fixable.

I checked system files. isdone.dll was present. Modified seven years ago—except the date didn't exist. February 29th on a non-leap year. isdone.dll crc check error

Then the cursor moved. Half a pixel. Just once. I’d seen isdone