Cannot turn on my PC

I think that the ram is not properly connected to your mother board.

You can:
1. Ensure that PC is completely switched off.
2. Open the case and identify the ram location
2. Unplug the ram and re-plug it into the same slot.
3. Turn your PC on.
4. If things are unchanged, do it again.
5. If things are still the same, it will probably the connection of the external display card (if you are using not an onboard display).

Hope it helps.

由於每一台電腦內所發出的B聲，會因BIOS廠商不同而不同，故列出每個廠商
BIOS B聲對照表http://computer.uwants.com/viewthread.php?tid=772167&extra=page%3D1
如果想知更多電腦知識,系統電腦教育中心有相關課程,詳情可參考實用電腦全科證書課程
參考資料： http://www.systematic.com.hk/computer.htm?id=18&sub=1071

電腦自測時冇發現ram之存在......
相信會是ram chip modal接觸不良，建議你先拔除電源線，再拆出ram modal，用擦膠擦拭接觸位，才插回記憶體插槽。

注意﹕拔、插記憶體，必須先拔除電源，確保底板無電；否則會燒燬ram model或底板。另外插入ram modal時，是直壓下modal直至扣鎖自動勾上；不能手動扣上鎖勾。