If everything was running OK under Windows 7, and if it has been less than 30 days since you upgraded to Windows 10, you still have the option to return your system to Windows 7 with just a few clicks. [And you still will have the option to try the upgrade again later, if you wish to, at any time before July 29, 2016].
To go back to Windows 7:
1) Click on the Windows 10 Start Menu icon
2) Click on Settings
3) Click on Update & Security
4) Click on Recovery
5) On the right-hand side, you wil see "Go Back to Windows 7"
6) Click on Get Started (just underneath Go Back to Windows 7)
It usually only takes about 20 minutes. You'll probably want to visit Windows Updates afterwards, though, to get any Windows 7 security updates that might have arrived in the last month.
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For the "DPC Watchdog" errors and Blue Screens -- these are often tied to driver issues. If you decide to try Windows 10 again in the future, before you do so, check on the manufacturer's support website for your laptop (such as Dell.com, Toshiba.com, etc.) and see if they have updated Windows 10 drivers - and possibly a Windows 10 BIOS - if so, you could download them ahead of time, and keep them handy if/when you decide to try Windows 10 again. Seems like USB, touchpad, and network drivers were causing trouble for some laptops. Driver updates from the manufacturers help a lot for such issues.
Advice: if your manufacturer's website mentions that your laptop is Windows 10 compatible - and you decide to try the upgrade again later - you can "clean install" a 64-bit version of Windows 10 [by downloading a 64-bit iso] and using entering your Windows 7 product key during installation (the recent builds of Windows 10 allow clean installs in this manner). You would, of course, need to backup all data you wish to keep (online, to USB drive, or DVDs) and then restore that data after the clean install, and you would also have to reinstall any programs. But you would finally be able to use the entire 4 GB of installed memory.
Most computers made in the last five years should run Windows 10 reasonably well (especially if they have 4 GB or more of system memory).
Let us know if you have any other questions.
