Weird HD and probably some other component's issue?

I don't think I can do a full cleaning, I'm still under warranty and IIRC that would invalidate it. But I can still try another compressor round with a more powerful stream.
The disk activity led is bleeping as usual, it unlits for a split second every 4 to 7 seconds... Which I don't think it actually did before, it was more of a costant lit-unlit thing. I pity myself for not giving more attention before, now I'm probably self-suggested to think that is now different. However the "unlit" status doesn't match with the slowdowns, they occur at different times, it's completely random. If I try to run a program like Speccy (and to write another symptom, sometimes not even desktop icons illuminate right away and I have to wait two seconds before I can actually click the icon, if I click before it's like clicking on a crashed program's window) it still shows 6GB of RAM, but I don't know if it can see this type of issues or it just checks whatever is plugged on the motherboard (again, even the Speccy analysis is slower than before).
Long story short, I'll try to blow some other dust tomorrow. Is the Bios default going to affect my personal datas or something? Or it just resets the BIOS' own settings?

IMPORTANT EDIT: I tried right now to play something on it, precisely a round with PPSSPP, PSP emulator (don't start a warez discussion please, I'm using games I own and I can prove that) and an old game, XCOM : Ufo Defense, to see the performance in both highly requesting and not software. They're unplayable: just like the computer's general behavior, every three seconds it completely stops in his tracks, and in case of the emulator (and probably XCOM too, I didn't go further than the main menu) the stuttering is costant, it barely registers my inputs and when it does a whole 4 seconds pass between my press and its receivement. Data loads fine, so the HD is safe I THINK, but the programs themselves run badly.

Last thing last, sorry for the wall of text, but can a stream of air damage the hardware if too strong? It's not anything crazy, a pretty old compressor, can I go full power if I need?

I'm bumping and updating the topic at the same time.
I blew the PC some more and the results are good: normal browsing on the internet and in the PC folders are perfect, I'm typing with no interruptions whatsoever. BUT, the software still stutter quite a bit. For example, while in the PPSSPP case it was barely possible to go through the main menu of the game I was emulating, now it's a smooth 60FPS - 100% Speed: when I get to the actual gameplay it starts stuttering again, like yesterday it stops for 2 second every 4. It's undoubtedly better than before, but it's still gasping for air. I didn't open the whole PC because I'm not sure about warranty, I used the compressor at max power possible. Can someone deduce where the problem lies? A more thorough clean helped a lot, can we find the root of the problem now that the patient showed improvement with the new medicine? .. Or at least I hope this is somehow related, maybe it's just a coincidence.

Edit: I tried to do a System Recovery to a previous situation but... No previous situation were to be found. What the heck. I created a new one but I've done that multiple times before, why did they get all erased?