Sounds like a slow connection, youtube shows a TIMEOUT error quite quidkly if the connection is crappy, but firsr I would try a handful of things....
1. Install the latest ADOBE FLASH player,
2. Try Using Google CHROME or Apple's SAFARI instead of internet explorer.
3. Install apple quicktime, microsoft silverlight (that way you have all the major downloads you need for sure.. latest adobe flashplayer too remember!)
4. Internet background speed loss: despite ALL the above, I still say it sounds like a slow internet speed. If you have a good internet speed and provider, you may just have a heap of viruses, trojans etc running in the background, sending info all the time you are online and using your internet connection up so much you can't play videos. It happens and it is common. Two options really...
A. Go to your windows control panel and open the internet security icon (icon looks like a castle wall), first do an update then do a FULL scan of your computer.
B. Also download the free version of MALWARE BYTES and again, update it and then do a FULL conputer scan.
These last 2 suggestions are a good thing to do regularly anyway, maybe once a month. If any detect a virus/trojan or anything, just delete it. It is all easy enough and self explanatory. These 2 programs search every file on your pc for know virus files, when it finds one it shows you, usually in red lettering, clickon it and press 'delete' or the equivelant, maybe it says 'remove' for example. There may be an option to 'remove/delete all' or something to that effect, this is the button you want as somethimes there can be lots of files that need removing.
snare x