About the power supply

It may just be time for a new one.

Do u mean i have to buy a new one or a new power supply

U mean i have to buy a new computer or a new power supply

A "common" trick over here in the states is to set that switch to 230V. When someone tries to turn it on it won't power up because the voltage isn't high enough. Not 100% sure what happens if you need 230V and its on 115V but I'm guessing it still won't start because the voltage still isn't high enough.

Needless to say I'm thinking your problems aren't what you think they are. If you got a new Dell then I'd suggest talking to whoever you bought it from and see about the warranty. Perhaps it was just a bad drive.