Could my Lenovo B50-80(80LT00FXPB) come dusty/be dusty after a month? And a whole lot of issues...

Alright, so i think there are some problems with my laptop.
Whenever i try to play some old games(example:Stronghold 1) it either starts beeping(i cannot really tell you the pattern, it seems to be 3long or 2 long and 1 short) or the fan speeds up a whole lot, or it gets hot as hell, or any of the above combined. This doesn't happen only when i play pre-2000 games which use 0% of anything due to ancient graphics. Now, judging by the requirements it should be no problem. I updated all drivers possible and can't find anything wrong in that regard. I've used 100 programs to check what's wrong, but it didn't really tell me much. Sometimes Speedfan shows too hot on all kinds of temperatures. Sometimes motherboard fails detection tests or it doesn't detect PCI and some 1 other thing i don't remember(I read somewhere it's supposed to be this way?). I didn't find anything wrong about it in HWInfo, there are no Hard drive errors(or if they are, the status still says OK).
Besides that, sometimes it likes to beep whenever, watching youtube, or just clicking stuff. Rarely screen flickers for a second(im not touching it). Very rarely touchpad stops working properly, it moves all over the place(alt ctrl del fixes this). Sometimes system seems to work slow alltogether.
Today Shockwave flash started to use 50% CPU in chrome on youtube/twitch.
Could any of these issues be caused by dust? I noticed the screen was dusty when i got it for the first time. Manual says it's impossible to access the fan in this laptop...So i was thinking about using canned air on the side vents.
I'm afraid this thing might blow up altogether. Any advice? Any guesses what's wrong? I thought it could be graphic card or motherboard problem but no idea what to do next.