Optiplex 9010 problem with login step of many applications ( Google drive , Dropbox, GitHub, Microsoft Account )

Hi
I have a Optiplex 9010 machine running on windows 8.1 Enterprise in the university, however, i have many problems with signing in into my accounts:

1) Google Drive : every time i restart my windows it get disconnected from my account.

2) Microsoft Account: when i want to connect my windows to my Microsoft account it gives 0x8004804e error !

3) Dropbox: it even cannot open a windows to ask me for my username and password but it is running in the background

4) GitHub: when i enter my username and password it says that username or password is incorrect but i am sure that they are correct ( i have tried online ! )

i think there is serious problem with my machine. i have reinstalled my windows 8.1 again but it does not solve my problem

I really appreciate if anyone can help me

Thanks