HP desktop won't start, red light flashing and beeping, loud fan

[Keebos]

Yesterday it was working just fine. I turned it off for the night and when I tried to turn it on this morning, a red light was flashing and beeping as well as the fan making a loud humming noise. I've read the the beeping and flashing means something. I didn't keep track of the number of flashes and beeps though. After the beeping and flashing I turned the computer off then back on. This time there was no red light, flashing, or beeping. Nothing appeared on the monitor either. After about 10-20 seconds of it being on, the fan started to hum really loudly again.

It's an HP Compaq dc7900. I've only had it for about 3 months and it was fine up until now.

Any help? Thanks.

[Checkurtech]

Hi

        Try to count the beep code and let me know how many beeps you are getting . Sounds like some sort of Hardware issue or failure so may need to returned to the store or to HP for replacement or service .

                                                   Checkurtech

[Keebos]

It only beeped and flashed the first time I turned it on. I didn't know that counting would have helped. Now it turns on and it seems to work fine besides that nothing shows up on the monitor, but then after a few seconds, the fan gets really loud.

[Checkurtech]

Hi
Due to the fact that you can't get a display on your monitor everything is pointing to failed RAM module ( memory ) . The beeps possibly were giving a memory problem that you experienced at first . All I can suggest if your not technically minded or would prefer not to do it is have your local repair centre do the repair for your memory . Let me know your thoughts
Checkurtech

[Keebos]

I'm not that good with computers so what I'm about to say will either be a good idea or something dumb.

I have another computer (it's dead though), what if I took the RAM from that computer and put it in the other?

[Checkurtech]

Hi
I understand your logic , but not all memory modules are the same type . If you give me the model number of both PC's I can check the specs of both machines and see if the Module type are the same .
Checkurtech

[Checkurtech]

Hi
Secondly and most importantly before you go mooching about inside a PC or Laptop computer you must be 100% sure all sources of power are disconnected before removing side panels or touching internal components . Disconnect all monitors ( PC ) mice , keyboards , USB devices . After disconnecting everything from the PC hold the power button down for around 15 seconds to drain any charge the Motherboard is holding .
Checkurtech

[Keebos]

My hp is a dc7900. My other one is an acer x1200. I'm more or a software person

[Checkurtech]

Hi
I'v checked the specs for your HP and Acer machines and yes it will be fine to cross over RAM modules they are identical in speed and architecture . Please don't forget the last post about removing the sources of power before you go inside the PC to check RAM . Other thing is if your HP has more than one RAM module remove only one stick first and try to boot . If it still won't boot with that module take that one out and try to boot from the other before you look to swap over modules from Acer machine . Don't forget to re connect your monitor to see if you get display with one / two etc modules . Post me back your findings
Checkurtech

[Keebos]

No luck 😞

I talked to a friend of mine and he said it might be a video/graphics card problem.