Windows 7 breaking down itself, limiting comfortable use (Virus?)

Hello, I have this huge problem that I am experiencing now on this HP Laptop that has windows 7 on it.
They are tons of issues, so I'm listing them:

Right now, the issues I am experiencing are many and they are annoying. First thing first:

THE ISSUES:

-The adobe flash player browser plugin doesn't work anymore. It doesn't matter what browser I use, it always crashes. I already uninstalled it and installed it again, but no avail. The weird thing is, it WORKS when I start Windows in SAFE MODE.

-Firefox crashes whenever I visit a page that uses flash player. This is really annoying. I could use youtube before because of HTML5 videos. Now, firefox crashes whenever it starts loading a video. Things like tumblr that has a webplayer on top crashes the browser too.

-I can't use Windows Photo Viewer anymore. This is when I started noting something was wrong. I click on a picture, and windows photo viewer runs in the background, but the program itself never shows up.

-I can't reproduce .mp4 files (and probably some others too) It doesn't matter what I use, Windows Media Player, Media Payer Classic, the programs both said they stopped working.

-Most programs I have straight out stop working. Just to name a few, Camtasia Studio, zsnes, DeSmUmE, windows desktop gadgets, and even modern Setup Host say they have stopped working when I start them. Other programs don't work properly anymore. The Commodore 64 emulator I have doesn't display anything when I load a game. Other programs seem to be fine.

-Something might be wrong with the system32 folder. I have PostgreSQL installed, and I use the SQL Shell to do my work. Whenever I try to list a table, it mentions "invalid argument: System32". It worked before.

-They are probably some other issues I have but im forgetting for now, or I haven't stumbled upon them.

WHAT I HAVE TRIED

I already installed and uninstalled the programs that don't work, but they still give issues. I haven t tried open them in Safe Mode, but I assume they would work fine, just like adobe flash player did.

I already scanned my computer to search for malware and virus with Avast, MalwareBytes Anti-Malware & Anti-Rootkit and Spybot Search & Destroy, and all don't give any glaring or high threat virus that could be doing this.

I already used the system file checker (sfc/ scannow) in an elevated CMD. It says that some dll files couldn't be restored.

I tried to use a system recovery to the point I know everything was normal, but guess what? The BS system recovery ALWAYS returns this error "System Restore: Could not access a file (error code 0x80070005)" I deactivated the antivirus and did another whole of stuff, just to waste my time and seeing it gave the same error all over again.

WHAT THE CAUSE MIGHT BE

Some Malware or Rootkit that is really damaging. I don't think there's another cause that could be breaking down my windows to the point of being annoying to use.

I remember seeing a couple of times that the CMD opened at randomly and saw something being executed. I searched for this, and it seemed to either be an attack, or an update of windows. Unfortunately, there's no log of the CMD after it closed, and it opens so fast I cant read what is happening.

Ad for HOW could I have gotten the virus? I think I can pinpoint how.
I did the TERRIBLE mistake of taking my computer to university to pass a presentation there. Then, some other people came yo me asking if they could show the presentation on my laptop. To not be rude or anything I said yes, but I think that one of those people USB might be the one with the virus. I scanned my PC after that, but I found nothing. But still...

ANTECEDENTS

The first thing I could probably pinpoint where things started to went down, was when the Java Eclipse IDE asked me to update Java. I did, but Eclipse IDE asked me to set up my HOME VARIABLE PATH, which it was there, but for some reason it didn't recognized it.

To sum it up, I derped out and ended up changing the wrong variable. I think it was the one that windows uses when a new program is installed, so it ends up being really long. I managed to recover the key with ShadowExplorer out of a system backup point. This is where PostgreSQL shell stopped working (giving invalid argument: system32)

I updated my AMD display drivers. I had an issue when I updated my display driver for the first time, sometimes when viewing youtube or sometimes randomly, the whole display would mess up (scrambled in horizontal lines, forcing me to hard reset). I updated it again and so far, no problems.

There's also the whole letting other classmates stick their USB device to my laptop.

WHAT I PLAN TO DO

I plan to reset to factory settings. However, I really don't want to lose all my files and I cant back all my files because I lack another HDD to use (I only have available an old 40GB one which I already filled up)

I planned to circumvent this by creating another partition, but as this is an HP laptop, it already uses them all (System, recovery, HP_TOOLS and where windows is located)

I found a tutorial to make the C: a logical partition, so I can then divide it to create the other partition, however, I don't know if I will be able to restore windows to its factory settings when the C: partition is set to logical, and that the new partition made of it (where I plan to store all my files) will be left intact.

Any input on what to do, or fix it would be greatly appreciated. It's really crippling using windows like this

DarKnight said:

You should definitely try Safe Mode,it's gonna answer to most of your questions about the issues.
Can you tell me when you noticed any of those issues for the first time? Did they "come" with a new OS ?

Hmmm, I don't see how safe mode will answer my questions.

I know that the programs might work, but then what? What could I do in safe mode to try and fix the issues?

These issues started appearing a little over 3 month ago. I have been using this laptop since 2012 with no issues.

You could try a clean startup - Troubleshoot Application Conflicts by Performing a Clean Startup
And another user account - User Account - Create

However, maybe the best option is to do a repair install - Repair Install

GokAy said:

You could try a clean startup - Troubleshoot Application Conflicts by Performing a Clean Startup
And another user account - User Account - Create

However, maybe the best option is to do a repair install - Repair Install

I tried a clean startup so I could install windows 10 and move away, but even then, I still got the errors

I also tried another user account. I have 3. The one I use daily, one for visualization, and one for university stuff.
I first noted problems with firefox on my university account. Flash would crash the browser, however my daily use account, firefox worked fine. Days later, firefox now crashed on all 3 accounts.

Hmmm, a repair install might do the trick, however I dont know if I can do it, as I don't have a windows 7 disc. This is an OEM laptop with Windows 7.
Can I still do the repair install with this laptop?

Thanks for the replies :)

Can you find any friend with a legit installation disk? Any edition will do (as long as it is the same bit version) - Windows 7 Universal Installation Disc - Create

Unfortunately, not

Of all the years windows 7 has been out, I have never heard of someone with a legit win 7 disc (They all pirated it :v) or the legit ones are form an OEM computer.

I suppose this leaves me to factory reset it, but I have this doubt:

I found a tutorial to make the C: a logical partition, so I can then divide it to create the other partition, however, I don't know if I will be able to restore windows to its factory settings when the C: partition is set to logical, and that the new partition made of it (where I plan to store all my files) will be left intact.

Clean Reinstall - Factory OEM Windows 7 Step 1 has some methods to get an ISO, but your options are limited.

I see. Will try out.

Thanks for head ups.