Hey, 

i am using win10 for 4 days now, and all went fine. except the one problem that pops up when i am shutting down my pc, where it says that there is a RAM defect x0000 or something like this, anyways, just clicked "OK" and its gone and the pc shuts down. 

But suddenly today, i started my pc and stopped at the login screen, and asks me for a password. Which i never needed before, and have not even got a password for my account. 

Anyways, I tried a few combinations out, sometimes randomly it accepts the passwords, says "WELCOME" and shows me the loading sign, but quits after a few seconds. The message I get all the time is "The Handle is invalid". 

How can I fix this? I dont want to install everything again..

Greetings

Hi MarcelKulhanek,

Based on your description, you cannot login the Windows now, right?

If so, the only method is boot into recovery console to repair the Windows:

Press the Power button at the Windows login screen. Then, press and hold the SHIFT key on your keyboard and click Restart.

Then you will boot into this UI:

Click Troubleshoot to go into next menu:

Here you could choose refresh/reset option to fix your issue. Note: this operation would erase your data. More information, read here.

Alternatively, you could go on clicking Advanced options into next menu, choose Startup repair or System restore to fix the issue.