Over the last week, my laptop (Compaq CQ62-251TX) which is 4 months old on the 12th of Jan, has started getting really sluggish again. If I start watching online videos (youtube, hulu, tvnz on demand etc..) the browser (I usually use Chrome but it does it in IE and Firefox too) starts to freeze, video stutters then the video stops moving, audio continues and the browser window goes grey, showing the program is un-responsive, then crashes. The computer is slow and near unusable for about 5 minutes after that, then it will work fine for a little whilte. Its done this once before, about 2 months ago. Ended with me making a complete disk backup and reinstalling factory OS. I've only installed about 10 programs (web browsers, photoshop, itunes, MS office, msn and skype), and the rest is just photos, videos and music. Surely this cant be normal for a 4 month old laptop? I've done complete virus scans and its not showing anything. Any help will be greatly appreciated. I'm going to reinstall the OS now, but what help can you give me so this doesnt happen again/or what could be causing this? Thanks GZ'ers.

Sam