Is the OS crashing or programs? Might need to update drivers and programs to Windows 10 compatible versions. Better to do a clean install of 10 than to upgrade imo. Some of your hardware might need firmware upgrades too. I had faulty firmware for my motherboard that conflicted with 10 somehow when I first installed it so I kept getting the blue screen of death every so often. Fixed it by updating the firmware. You can find the firmware for your hardware on the manufacturers' websites.
With that being said, I love 10, but I have to find a copy of 7 now because I found out a few days ago while modding an old dx9 game that 8 and 10 cripple (modified) dx9 apps by limiting how much RAM and vRAM they can use to only 4GB combined and the devs at Microsoft seem to have no intentions of fixing it. On 7 there is no limit , but a bug in 8 and 10 prevents this from working properly. Makes a lot of my older games unplayable after being modded. Microsoft support sucks as always though and have given no feedback to the thousands of complaints other than acknowledging its existence and that it's their fault.
So... Guess I'll be going back to 7 myself for a while if I can find a copy.
But really, other than the dx9 bug (really only affects modded dx9 games) and privacy concerns (which can be fixed), 10 has been pretty solid imho. Way better than the abomination 8 was and a good step up from 7. The main thing is to make sure your drivers, firmware, and programs are all updated to run with Windows 10. Windows does install generic drivers for a lot of your plug and play stuff, but sometimes it's better to get the official drivers from the hardware manufacturers. Sometimes not. Just depends. But doing all that might solve a lot of your buggy/crashing issues.