Computer is extremely slow and hangs but runs perfectly in safe mode


Oct 20, 2016
as the title says, and i can't figure out whats causing it.

first time it happens were a week ago when chrome gave a "waiting for cache" message at status bar and did not connect, firefox worked. i thought its chrome's problem so i did my best to fix it even re-installing few times and then removing it completely but then the problem reappeared and wouldn't go unless i restart the laptop.

Then after restart it would work for few minutes and get stuck at a task again (specially if opening a new software or even a window's explorer window.. or switched between tabs)

I did a clean windows 7 install when i gave up and it worked smooth for two days but it reappeared now restarted few times still happens after few minutes.

when i tried safe mode (didn't occur to me before :'D) it worked flawlessly, writing this in it now..

i can't figure out what is causing it! i disables all unnecessary startups but nothing worked not even disabling avast's shields (the anti virus im using, free one)

and i can't even open task manager to check what is causing such a huge freeze to the point Task Manager doesn't even wanna start!

weird thing is i had this version of windows for a long while and i installed nothing new or anything it just happened out of no where!

Update: I tried windows startup repair, and after it finished it wouldn't log into normal or safe mode..! So i reinstalled windows again.. normal mode is laggy still so im in safe mode now, again.
thank you in advance :)