Question Blank display and hard drive not booting, tried a bunch of stuff already that didn't work

[KittensEverywhere]

I sure hope folks here can help me out. I've shared my issue on two other sites with zero responses. I've got a Lenovo Thinkcentre A70Z All-In-One desktop that runs, but the screen stays blank (as in it doesn't come on at all) and it seems that the hard drive isn't firing up either since the hard drive icon doesn't come on anymore.

Things I've already done, none of which worked:

• Hard reboot
• Normal reboot
• Taking out the battery and putting it back in
• Resetting the BIOS with the CMOS jumper (screen stayed black, computer lit up but didn't start, motherboard made a light whirring sound)
• Reseating the RAM, both removing/reinserting and swapping the RAM sticks around
• Nudging/reinserting/generally messing with bits and pieces to make sure nothing's loose

Things I already know:

• Everything lights up normally. The LED is green, the motherboard is on, and the fans are running.
• Computer has not been dropped or damaged recently, nor have there been any issues like power surges or shutdowns during updates or anything like that.
• When I played with the jumper the first time, I got a series of beeps. Three short and one long, which according to some info I read regarding beep codes for Lenovo systems, suggests an issue specifically with the security chip, but when I did this same exact thing again, no beeps. I was able to get the beeps again when I took out the battery and booted up without it.
• Last time I got it to turn on, I did a system restore to a previous point - about 2 months before it started acting up. This didn't work, but it did work when I had this same problem a year ago.
• Given that the issue occurs immediately, I have to assume it's a hardware problem and not software-related, but I might be wrong.

I'm assuming it's probably the motherboard since it hasn't responded to any of the stuff I tried. Other things that I found that could be the cause include the power supply, the processor and the video card, which I don't even know if I can change that since it's integrated. I have read that removing a RAM stick and leaving it out entirely could help, haven't tried it yet. And if it helps, these are the computer's specs:

• Processor: Intel Core 2 Duo E7500 @ 2.93GHz.
• Operating System: Windows 7 Professional 32-bit.
• Memory: 2GB DDR2.
• Hard drive: 320GB SATA @ 7200RPM.
• Graphics: Intel integrated HD.
• Wireless networking: 802.11b/g/n.
• Sound: Integrated HD audio.
• Optical drive: Slot-loading 8x DVD+/-RW
• Additional stuff installed: Wacom tablet

Is there anything else I've missed? Should I be shopping for a replacement motherboard? I really like my computer and if I can affordably salvage it, I'd like to, but I don't know if it's FUBAR or not.

 

[Grobe]

Your system is like nine years old, right? I have had some computers during many years, and when it cames to motherboard and PSU - those components in my opinion is the first that fails (hdd's not mentioned). I have had motherboards that failed 6 years old and I have had motherboards that was more thean 10 years old, depending on their build quality and usage.

So based on my own experience I would assume that the motherboard is the most likely part failing. Have a visual inspection and look for damaged electrolyte capacitors. Look here so you know what to look for:
https://www.robotroom.com/Faulty-Capacitors-1.html

If you find one, then that is the point of failure.

 

[KittensEverywhere]

Your system is like nine years old, right? I have had some computers during many years, and when it cames to motherboard and PSU - those components in my opinion is the first that fails (hdd's not mentioned). I have had motherboards that failed 6 years old and I have had motherboards that was more thean 10 years old, depending on their build quality and usage.

So based on my own experience I would assume that the motherboard is the most likely part failing. Have a visual inspection and look for damaged electrolyte capacitors. Look here so you know what to look for:
https://www.robotroom.com/Faulty-Capacitors-1.html

If you find one, then that is the point of failure.

Thank you so much for responding! Yes, my system is in its winter years. And while I can't remember every nook and cranny on my motherboard, all the capacitors I think looked like the ones you linked, but I thought it might have been normal since they were all like that. I'm not a tech person, but I'm trying to learn how to fix my own stuff and I'm not very knowledgeable in all this just yet.

The upside is I know I can get refurbished copies of my very same motherboard on eBay, which is fine for me. Problem is I think it means reinstalling Windows, which I don't know if I can do because I got the computer secondhand and I don't have the Windows disk or any of the original installation/license goodies.

Edit: Okay, I take back what I said before. I took a better look at my board and none of the capacitors are poofy, leaking, uneven or anything that looks out of the ordinary. Doesn't mean it's not still the board, but that part of it is okay.