BSOD, Then random computer crashes when playing, freezes on startup.

I tried to kind of do what you said earlier, I opened the computer case, cleaned out all of the dust (there was like a 2cm layer of it on top of things) and un-plugged and re-plugged everything back in. However didn't help.

Here is basically what I do :

1. Result from yesterday
I come home from school, turn my pc on :
Boot #1. I get until the windows screen (i put in my password) stay on the desktop for like 2 minutes, check skype, email etc, mouse freeze and pc shuts down in 15 seconds.
Boot #2. PC starts itself automatically, 5 seconds of rumbling and nothing on screen, shuts down.
Boot #3. ^ again.
Boot #4. ^ again.
Boot #5. I get through BIOS screen, and it asks me to select "Auto Launch Repair Option" (or something like that, can't remember) and it has a descripton of fixing the windows launch up. I click start windows normally, and everything is okay.

2. Results from Today.
Boot #1. Windows screen (The 4 coloured squares flashing for like 30 seconds - longer than usual and shuts down)
Boot #2. PC starts itself up automatically, 5 seconds of rumbling, black screen, and shuts down (I can hear it running and then stops)
Boot #3. ^
Boot #4. I get through everything, I login using my password, use the desktop for 2 minutes, freezed mouse and crash.
Boot #5. PC starts itself up automatically (like boot attempt #2)
Boot #6. I select start windows normally, and everything is normal.

This confirms what you have described before.
Were you able to do any tests?

Unfortunately not, Im basically a newbie in this kind of stuff, and I don't want to do anything wrong in case everything just breaks. Is there anything easier to do?

Not much that would be directly helpful.

If you are uncomfortable working inside the case then I highly recommend taking it to a repair shop, or find someone you trust who is capable working with PC components.

Got a new BSOD today. Just after my mouse froze on the desktop. I couldnt get a picture of it because it dissapeared too fast, but I attached a minidump file to this reply so you can have a look at it.

You should post that over in the BSOD Help Forum.
The guys over there know how to read those dumps. I don't.

Link to it here.

Did as you said, 1 successful boot yesterday, and today a new BSOD.

I attached new minidump file.

Another one today. I was not watching the computer so I dont know if it is the same or not.