As a rule of thumb for this kind of problem, I always try the procedure as follows:
1. Check the fan on CPU.
Due to the security issue, computer will never startup if the fan on CPU is not working.
2. Check the power supply.
This can be done by replacing with a new ones or the one which is workable in other computer
3. Check the connection of RAM.
If you have two RAM on your computer. Remove them out and install them back one by one if the problem is solved. The best way, of course, is use a RAM which is functionable in other computer.
4. Check the heat-sink of the CPU.
Again, due to the security issue, computer will never startup if the heat sink of the CPU is loosed.
To sum up, all the problems above will cause a desktop or computer not respond and trigger a long beep or buzzing noise to alert users. Therefore, please try yourself before sending your computer to so-called "expert" for investigation unless you have a warranty or a trusted "expert".(Besides, this can save you a lot of money)
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Written by: Xaivier Chia
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