I didn't know where to post this, so feel free to move it if it isn't in the right section.
I have a problem with my computer which has become slow, and only while on the internet. I noticed that it has slowed down too while turning it on: more time than usual to load the "enter password" screen and more time than usual to load the desktop after entering the password.
I own a laptop, Acer Aspire 5742G with 640Gb HDD showing 358Gb free out of 583 and 4Gb DDR3 memory. It is a year and three months old, and is regularly cleaned of junk files & registry errors, defragged, and checked for malwares/viruses with avast! free.
I use Mozilla Firefox, and encounters several problems of slow response from the laptop. When I scroll down (using either the pad, the arrow keys or the sliding sidebar), the page will regularly freeze then scroll down on itself as much as I scrolled while it was frozen. While typing, the screen will freeze, then all the letters typed when it was frozen will appear at once. While clicking on a field in order to write in it, it will take time to show the small intermittent bar "|" that says I can write in the field. While passing the arrow of the mouse on a link, it will take several seconds to become hand-shaped instead. While loading pages, sometimes the loading circle on Firefox will freeze, as well as the rest of the screen, then resume loading.
Please note that during these "freezes", the mouse cans still be moved, that slow response to typing will not happen on Word or in My Files/Start search, and that clicking response is fine in Start menu or on desktop files. I always use the laptop upon a hard surface to avoid overheating, and never put it on the bed, for instance. Videos never slow, once they are loaded, they play just fine.
Tried up to now to solve the problem:
-CCleaner used to clean junk files, fix registry errors and disable useless programs that started at the same time as Windows in order to make the starting faster
-updated Firefox to latest 13.0.1 version, which seemed to solve the problem for a moment before it was there again. Actually, restarting Firefox makes the problem go away, for the first few minutes. It starts then getting slower and slower.
-defragged HD with Smart Defrag
-scanned for viruses/malwares
I haven't yet tried restoring the laptop to a previous version, neither did I try formatting the HDD. This is my last option if nothing else helps. I really am at a loss about what might be wrong. Thank you for the time my problem will be given, whatever happens.