I had an unrecoverable system crash in April which means that there are three tasks associated with that computer which show up under my account as "In progress".

Is this the best board to report this?

Computer Name --- david-446186d30 ----- Windows XP
Task Names
wah2_eu50r_mvs1_201512_13_561_010991328_0
wah2_eu50r_mt7h_201512_13_561_010987996_0
wah2_nawa25_a1db_209512_13_491_010822245_2

I have suffered the same issue in the past. From memory when it has come up before the answer has been to just wait till the tasks time out. Your three tasks if re-instated would be relatively insignificant alongside all those where no attempt is made to report that they won't ever be finishing.

This is very different of course on projects such as climate@home which is in alpha or if beta testing for a project when three tasks might make up over half a batch.