Forgot to mention another Firefox issue! When searching something in google, and opening a link to a website, it redirects me to another search website several times before actually bringing up the website that I'm trying to get to. Probably not that much more help on top of everything else I've mentioned, but thought I'd tack that on as well!
I've had this problem for about a week now, and it's getting to the point where I'm running out of ideas for what to do!
A couple of weeks back my computer ended up with the virus (I can't remember the name of it, unfortunately) that pretends to be an XP virus scanner that tells you that your system has a virus, shuts down your other antivirus programmes and your internet until you buy a license for their full 'product', which then gets rid of their virus. I created the registry fix that was suggested on several websites, and the virus went away perfectly fine.
I thought that was it, but since then, my computer's been behaving in increasingly bizarre ways.
The main problem is with Firefox- it crashes constantly, and every five minutes or so, will throw up a new tab that either leads to a gambling site or a search site with search results to something that I might have searched in Google previously. It crashes constantly, especially when opening new tabs, and closes itself down without warning quite frequently, whereas before this whole issue it's worked perfectly.
On my computer itself, I've had the start bar changing itself back to the grey Windows 98 scheme several times, and at the same time the windows audio device stops itself so that my audio stops working. When starting the audio device again, my sound settings change themselves back to the original Windows audio scheme (with the noise for emptying the recycle bin, opening folders, etc, whereas I usually have all Windows noises muted), and when I change the scheme to no noises, it tells me that they've all been muted but they still play when they should (for example, when emptying the recycle bin).
My computer's also having increasing trouble shutting itself down- every time now, it brings up several 'this programme is not responding' messages and then crashes on the closing down screen, whereas before, again, it's closed itself fine.
Also, in the C:/ drive I'm finding my free space is vanishing constantly. I should have about 10GB free on that drive, but it's always lingering around the 200mb stage, with this remaining space constantly vanishing and making my computer stall and crash like crazy.
There's a whole load of unrecognised tasks in my task manager, too- things like:
all under my username (as opposed to system or network service etc). I've never seen these in there before, haven't installed any new software, and suspect they may be something to do with what's going on.
The last (and weirdest) thing was just a second ago- I had iTunes and 3DS Max open, and suddenly this audio starts playing on my computer- some lecture about ADD and child psychological issues and how they're not just mental issues but real physical diseases. I shut down both programmes and every background process that might have been causing it, and it continued to play until I shut down my computer completely. Possibly the strangest happening yet!
The reason I'm asking for help is that my antivirus (AVG) and my spyware programmes aren't picking up anything wrong whatsoever, but there's definitely something on my system- so I need to know if anyone knows what it is, how to get rid of it (I'm happy to install new antivirus programmes or whatever, so long as I don't have to pay for them- poor student!).
Any help would be incredibly useful- thank you!
System: Windows XP
Antivirus/etc: AVG, Ad-Aware, Spybot
Internet browser: Mozilla Firefox