I've been running Windows 10 build #10130 for a couple of weeks now. I had some issues with this build until I downloaded the newer fix. Some quirks I notice include slow start on initial login. The IE browser sometimes takes more time to open and keeps thinking and thinking. Once in a while I get a Critical Error dialog :).
Alright! It's more than a few.
I have a Sony Viao Pro 13 with 8GB RAM, Windows 10 build #10130 (upgraded Windows 8.1). Today, I left my laptop running for a couple of hours and when I got back, I saw a blank screen or black screen. OK, call it black or blank, I wasn't able to see anything on the screen. I couldn't even see the mouse pointer. I tried cold boot. Same results.
Finally, after reading a bunch of stuff on the Internet, here are a few tricks you may try.
1. Try to cold boot your machine a few times (3 or more) without fully restarting.
2. Try running in safe mode.
3. Try using your disk to reboot if you installed from a disk.
If it still doesn't work, remove the power and take off your battery.
I hope this problem goes away when we see the final Windows 10.
Good luck!