I have a dell inspiron n5010 with dual boot (windows 7 and ubuntu). It was running fine earlier but suddenly it started mistyping letters with multiple letters and special characters for 1 sec and then shuts down. After that laptop was not getting started for a while. Few hours later it again started (with ubuntu) and did the same once i pressed anykey on keyboard. but now computer is not getting started at all. power led goes on for one sec and then shut off without starting fan or booting till bios. Same cycle of on and off without anything on screen or beep sound is repeating.

Initially while misprints were happening i checked all keys in keyboard, pressing numlock, combination of numlock and other keys. After that i tried discharging static charge by holding power button for while without any power connection. I disassembled the laptop to clean the fan and check for any burns inside but everything is fine. I reassembled but still its the same. Tried starting without battery with power supply / with battery without power supply /with both. Nothing is working.

If it is still under warranty, take the disk drive out and send it in for repair/replacement. The OS on the drive is likely ok, hence the advice to keep the drive, otherwise they will replace that also, and you will lose all of your data. Dell hase (in the past) been pretty good about dealing with this stuff - and if it is out of warranty, the cost will be minimal for a motherboard replacement.