Monitor loses signal after a while, reboot fixes temporarily.

Hey guys.

So, everything was working just fine until this very morning. No headaches whatsoever.

So, this morning I turn on my monitor and receive a "HDMI No Signal" from my monitor. Thing is that, 8 hours prior, it was working just fine. So, here's what I've done.

* Monitor was connected to a self-powered HDMI switch. Connected directly instead. No signal.
* Electric reset. Nope
* DVI. Nope.

Until, I bit the bullet and pressed the reset button while my monitor was connected in DVI. Lo and behold, signal! HDMI worked too. So, after an hour no problem, I had to attend some business in town then visited my father. When I came back, my monitor... had no signal once again.

So, I pulled off an old 24" monitor (1920x1200) off my closet that was going bad on one side but was still working, we could still see something. Connected DVI on it (no HDMI). No signal. So, I put my main monitor back in place through HDMI and reset. Voilà, once again.

So, checking my temps now, it's definitely not overheating. My graphic card idles at 36oC and my CPU is ~45oC (it always does a little something all the time - 5-10% use).

I will be trying to update my GPU drivers although I don't have a lot of faith in that and I can't really test my GPU in other computers.

Also, of note, when booting my PC, it does a single bip meaning everything is A-OK.
Another note is that one of my HDD is in the red with 5 unstable sectors and the BIOS logged a SMART event because of that (replacement HDD on the way).

I will be using my PC too so when it'll happen, I will know what exactly happens.

I'll be updating.

Thanks for the help in advance, guys.

Found out that, somehow in Power Options, that Windows would turn off my monitor after 20 minutes (I don't remember setting that option to that value, ever). But that doesn't solve my problem because the first time it happened, my monitor was actually powered off. It might be something that updating the driver did though...

Looking at Event Viewer in System events, there's a totally empty space between 13:28pm and 14:52pm. During the night, 4:53am and 9:30am. However, at 9:30am, there are events between and the reset (Critical event) at 9:54am meaning that my PC was still working somehow.

It's really weird though. PC has been running for 2 hours 40 minutes now.

EDIT 26/10/2014

Alright, I'll be doing a test. It just occured to me that my PC, after being left unattended for ~20-25min, made the problem occured last time. So, I'll go and watch TV for ~30-45min. My work will be saved in case it happens.

Went to bed at 8pm exactly for a bit of sleep. Closed my monitor. Woke up 10pm and fired up the monitor. It still worked. But wouldn't through my self-powered HDMI hub. Well, anyway, as long as it works directly plugged-in on my PC, I'm happy. Next time will be the final test where there will be a long period of inactivity.