MYISAM Table Crash After Electricity Down

[Eko Prasetya]

Hi, Everyone

I work with Mysql database.
Which has 2 Million records.
one day the server has goes down because the electricity down.
When the Server has started again, suddenly an error has occured
(e.g. 'DUPLICATE ENTRY ....) and table speed reading has becoming slow.

I've been trying to solve the problem.
drop an index and build again. and doing a maintenance table like :
analyze, optimize, repair. the problem is solved.

But I wondering, is :
1. Mysql table have to maintenance everyday, especially analyze, optimize?
2. Mysql table can crash because electricty down?
Please someone help me to answer this question... thanks a lot