Non booting computer problem.

HP pavilion desktop. Fan comes on, power on light comes on, no Bios and no boot. HP Pavilion Desktop - 550-a114 If I remove the RAM card completely I get 5 beeps. If I reset the card in the second memory slot I get nothing once again. So does this sound like the memory card is bad, or the motherboard, or can’t tell.

The Five Beeps is their “I can start, but I don’t have any memory” signal. You might still have a motherboard problem, but a memory stick short is possible.

One quick check: look closely at your USB ports. They can break due to someone tripping over the cord, and much later, the plastic piece that keeps the contacts in line falls out, and the next time a USB cable or stick is plugged in, the contacts short together.

If those are okay, the best thing to try first, is a different memory stick. But it’s possible that the boot process for that motherboard stops as soon as the lack of memory is detected, and only progresses to the point where it finds the short that’s in the board itself, after it sees that there is memory.

Good luck.

Also check some simple things. It sounds like it turns on, but there is nothing on the screen. Is the monitor connected and coming on correctly? Is it set to the correct input?

Yes, the monitors work with another computer. The fan comes on but the disk drive never engages. If I remove the RAM it does give 5 beeps.

If my system cannot detect a hard drive, there is no bios screen or anything. Maybe your drive went bad?
Reinstall to another drive or borrow one with a system on it and see if that boots.

Swapping boot drives around can lead to all sorts of unnecessary problems with Windows OSes.

No need to swap boot drives. Take the drive out of the dead PC and add it as a secondary drive to another PC. From there you can do various tests on it.

But if the OP isn’t getting any BIOS screen at all, then the HD isn’t probably the problem. The problem is more likely in the PS, MB, CPU area. But one can always hope that by disconnecting and reconnecting all the cables and cards maybe that’ll fix it.

I would suggest doing this and backing the drive up would be the first thing to do while it is still possible.

Probably correct. I tested after posting, ( should have tested before )by pulling my hot swap drive. Got BIOS. Must have been some other problem with my PC, that was inadvertently fixed while messing about with the drives. Was transferring system to a new case.

I don’t mean to keep sticking on this topic, but I like clearing the simple stuff before moving onto the more complicated, and I’ve seen it happen before. Some monitors are very bad about switching inputs, so if, for example, you connected a laptop over VGA to the monitor and it works, but the non-working computer is connected over DVI, then the monitor might not switch back to DVI on its own. There might be a button to cycle through inputs, or to auto select the active one. This can be very annoying to test, because some monitors turn off immediately with no input, but take a 5-10 seconds to come on with input. Also check the video cable at the back of the computer, and where it plugs into the monitor. Usually it is best to unplug and re-plug both ends of the cable, even if it looks like it’s plugged in.

Assuming none of that is the problem…

If the hard drive never spins up (usually you can hear it), that might be keeping the computer from starting. I’ve often seen dead hard drives cause the boot to freeze. That usually happens on a BIOS display, but maybe on your computer it happens sooner. To test that, all you have to do is unplug the drive from the computer. Assuming it is a SATA hard disk (and it should be if the computer is less than 10 years old), just unplug the small connector on the back of the drive.

With the drive disconnected, obviously the computer won’t boot to Windows, but if it comes on and gets as far as giving an error about no boot device, then you’ve isolated the problem to the drive.

Another thing to try is resetting the BIOS. Often there is a header on the motherboard which when shorted will reset the BIOS. It might be listed in your manual, but possibly not. If it’s there, it should be two pins sticking up on the motherboard, labeled BIOSRST or something like that. If you can find it:

[li]Have the computer off.[/li][li]Short this pins. The best way to do this is with a little jumper, but you can use a screwdriver or something else if you’re careful.[/li][li]While the pins are shorted, turn on the computer for a few seconds.[/li][li]Turn off the computer.[/li][li]Remove the short.[/li][/ol]
Then turn the computer on. If the BIOS comes up, you might have to go into it change any settings that weren’t default.
You can try an addon video card, if the video is built into the motherboard, or a different addon card if it uses an addon card. Unless you have a box of old computer junk, finding one to try might be difficult.
I haven’t had this problem in 10-15 years, but you can check for leaking capacitors. Those are the cylindrical things scattered around the motherboard; probably concentrated near the CPU. Look for any with a domed, instead of flat, top; or that are leaking goo; or have some discoloration on the top. If you find bad ones, then the motherboard is finished. There used to be an epidemic of bad ones, but like I said, I haven’t seen it in a long time.