There is no 'hardware acceleration on youtube' unless you were using a specific application written for youtube to 'tap' a video card to assist on making it better. I think somethings got jumbled up in how it was presented. Since we don't even know what computer you have, can you please help us do some 'basics';
Download and run SPECCY, copy and paste the first tab info to here
Remove whatever AV your using and go to www.filehippo.com and download AVAST! or AVG and do a full system scan - this repeatedly has resolved alot of people issue relying on MS Essentials.
Download Malwarebytes do a full system scan (AV doesn't pick up alot of malware) - this resolved almost ALL other similiar posts to date as most had Malware the AV didn't pick up.
Repeat the AV/Malware scans till the system comes up clean.
Did you install all Windows Updates? Including options except BING? Check them and repeat till ALL are installed.
Download and run Slim Drivers, install all the latest updates but you don't need to reboot until you do the last update
Go to
http
/java.com/en/download/index.jsp download the newest JAVA.
Go to http

/get.adobe.com/flashplayer/ and follow the instructions to INSTALL flash
Let us know the results of each.