[SOLVED] New pc build, first boot worked and launched to desktop. Next time i turn it on it won't even go to BIOS screen

[joebyy123]

Hi guys,
Recently spent the past few days building a new PC (first time builder) with the following parts (new and from old pc):

• AMD Ryzen 5 3600
• MSI B450 Tomahawk Max
• 2 x Corsair Vengeance 8 GB RAM
• Crucial MX500 2.5in SATA SSD 1TB
• Old 250GB SSD with windows installed (old install)
• 650W PSU (from old pc)
• 1TB HDD (old pc)

Anyway, i put it all together over a few days and turned it on last night without the old 1 TB HDD from my previous build and the sides still off, cables not managed etc, SSD not mounted, to test everything was working. Computer boots fine, launches to my old windows desktop.

All good, so i power it off, plug in my 1TB HDD, manage all the stray cables, mount the SSD to the case wall, put the sides back on and power it up. Now, the computer wont even boot to the BIOS screen and theres a red CPU light on the motherboard.

Strange, so i unplug the 1TB HDD as i assume this is the only thing thats changed and try again... No luck, the computer still wont boot to BIOS.
Any ideas what might be the issue? Only thing i can think of thats changed since it originally worked is that i've mounted the SSD onto the case's wall with cable ties which might be shorting it out or something? But i dont think that is the issue as there is still power (fans, rgb's etc all come on).

 

[rocktalkrock]

First double check all the power and SATA cables are still plugged in properly. Then clear the CMOS and go back to booting with just 1 drive connected. You can also try reseating the RAM sticks, that has worked for me in the past.

 

[joebyy123]

First double check all the power and SATA cables are still plugged in properly. Then clear the CMOS and go back to booting with just 1 drive connected. You can also try reseating the RAM sticks, that has worked for me in the past.

I've installed the RAM as per motherboard instructions, ie. its in the right slots.
Also, as i booted to desktop previously it surely couldnt be the RAM thats the issue as i've not touched it since, could it?

As the CPU red light(indicating CPU not detected or fault) is on im leaning towards it being a fault with the CPU or the CPU power plug is not connected fully. If the SATA cables werent correctly plugged in the PC would still boot to BIOS wouldnt it?

I'll try all your suggestions anyway, but whats your thoughts on the above?

 

[rocktalkrock]

Pulling the Ram sticks out and putting them back in has worked for me in the past. I can't explain why, it just has. The most likely reason your PC will not boot is something was accidentally knocked out of place while installing the last parts of your build or one of the cables is faulty.