DELL laptop beeps once during start and does work after start

Hello,
Recently, my laptop key '5' was not working and it would type automatically.
Now when i start the laptop it beeps once and the windows screen opens. But the cursor blinks continuously and i can not open my computer or other folders or any program as clicks wont work. Moreover after few minutes it may work absolutely fine with normal speed. PLease help.



<config>Windows 8 /