The indicator lights on the back of my dell dimension 4400 are g g g y.it was working fine now wont boot up.

I think that the cause of this problem is your cpu or ram

Try F2

check RAM and graphics card if additionaly installed.., try to remove and reinstall. make sure power connection is disconnected while doing this!

It seems like it that you have a faulty power supply. Also the motherboard may be damged aswell, But most probably you can fix your PC by changing the power supply.

Flashing Amber power LED indicates a bad power supply.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817822008&cm_re=atx_power_supply-_-17-822-008-_-Product

A solid power LED is either a bad component connected to the motherboard or a bad motherboard

yes, you can only download cd´s/dvd and install, now linux has 90% computers companys, on database, but you can check on mandake website.

reload the windows, it missing the loading operating files.

I’m happy to help further over the phone at https://www.6ya.com/expert/mustafa_06f84c65ab5cc745

check power supply in back to see if you have on and off switch but you would'nt be the first with this problem from dell about the power supply going out meaning:

if you don't have nothing happening when your trying to boot the computer then it's the power supply, plug in computer power up and feel in back to see if the fan is blowing if nothing power supply is gone call dell.

if this is happening from a cold start press Ctrl Alt Del, it should boot ok, then, if it still persists make sure the system is set to boot from hard drive in the bios settings

inside the pc there should be a green light. called flea light. if its not on.. then id say motherboard or power supply are bad.
take power cord off. and hold power button down for 10 ecs. then reconnect and retry. i think its abad psu.