My desktop PC is behaving a little strangely over the last few days.It is a self built machine running 5 operating systems managed by BootIt BM. I have Win XP Pro, Win7 Ultimate 32 & 64 bit, Ubuntu and Win 8 Enterprise trial. The problem I an having is with the Win 7 installations. It started with Google Toolbar becoming invisible. It is installed and enabled but all you can see is a grey line with an X at the left hand end. No icons, search box or wrench icon are visible. I just thought this was a problem with IE as I had fairly recently installed IE10. My day to day OS is Win 7 64 bit and this is where I first noticed the problem. I searched for problems relating to toolbar and Win 7 64, founfd some bits but nothing I tried changed anything. The other noticeable thing was that whenever toolbar dissapeared the browser would become unstable and would throw up Script errors, particularly when trying to launch another web page. IE itself would often also freeze.
I am running Bitdefender TS 2013, scans from which showed nothing. I have also scanned with Malwarebytes, Spybot and Superantispyware, none of which revealed anything other than the usual cookie reports. I also did a rootkit scan with spybot but it didn't show up anything that I thought was significant.
The only other thing that makes me think it might be some sort of virus or malware is it wont allow me to download certain things, such as Superantispyware. I had to download the portable version via my laptop to use it. When I try and download it I get as far as the 'donload beginning now' screen and that is it.
I am still not convinced it is virus related but I am at a loss as to which direction to go in to find a solution, so any help you can provide will be appreciated.
Incidentally whilst searching for a solution I have come across several other people with the same problem, none of whom have found a working solution.