Having a problem in 2 diffrent browsers

A while a go, I used to use Firefox - but it started to have some problems, whenever I had 3+ tabs opened at the same time, it stopped working. Now, I can't even open 1 tab and it simply stops working. I can only open the inital page -- I've reinstalled the program, cleared the cookies, history and all that *** and it still doesn't work.

My other problem, is with Google Chrome. I switched to Chrome because Firefox wasn't working properly, but now it seems that Chrome isn't either. It works just fine at first, but after using it for a few hours it starts getting slow. It starts to take like 10 seconds to open YouTube or Google, any website at all! I restart the browser and same thing happens, only solution is to restart the PC.
I've also cleared the history and all that on this one, reinstalled multiple times and still nothing.

It's not an internet problem as it works just fine once I restart the PC.

Any thoughts on this?




Thanks in advance.