i have a trouble on my pc, when i startup it takes too long time to get respond how is it possible?? can anyone suggest me any maintenance task??

Assuming the problem only occurs during startup, it is probably either the drivers you are loading or programs you load with each startup.  You did not specify which operating system you are using but there should be a startup log available. 

Check the startup log for errors and retries on starting drivers and programs.  If there is a problem, reinstall the driver or program.

Check the list of programs you are starting.  If it has been a long time since you rebuilt your computer (Microsoft, at least formerly, recommended rebuilding your system every 3-6 months).  There may be all sorts of programs that are being started in the background.  Once started they just sit there waiting for being re-called into execution.  For most it is just a way of preventing long waits when you want to use the program, but if you do not want them staged for you, remove them from your startup.

If you are having problems after startup, that would suggest malware of some type (viruses, hijackers, ...).