Keyboard Stops Working After Windows 7 Installation?

I have a Toshiba A300-18A laptop, bought in Portugal in 2008. It came pre-installed with Vista and I always left it in place because I couldn't find a proper time to backup everything properly. These holidays, I finally had the time to do that and 2 or 3 weeks ago I installed Win7. I didn't do an upgrade and did the custom install over the previous Vista version. Right after installation, during the first uses, my keyboard froze during an internet session. Simply, no key would work, but I had full control of the computer otherwise. Over the next days I found it happened quite frequently, and it didn't even need to be on internet. The most often place to freeze is in text editors (ConText, TexnicCenter), Excel (I'm using Office 2007), an online MMO and even the login screen, before I can actually access my computer. A restart usually solves the problem temporarily, sometimes I need two restarts in a row.Due to this, I did a reinstall of Win7, this time formatting the C: partition where I was making the installation. So this was a real clean install and I still had the same problems. I thought it would be drivers, so I installed some drivers I downloaded from Toshiba support center and THEN I found out about Toshiba's Win7 installation.Still the same problems. There are more curious things about the keyboard: it usually seems to think ctrl is pressed. I have opened the on-screen keyboard and noticed the ctrl-key depressed. Unpressing this key, thought, does not rehabilitate the keyboard. This ctrl-press must not always be on, thought, because sometimes I notice parallel behaviours and other times I don't. For example, I don't get 'save file' dialogs if I press 'S', but I do see the screen zooming in and out in a web browser if I roll my mouse-wheel. Also, I have some defects in Office (namely Excel) that I think may be related, and this since my first install: sometimes I'm going to Open Excel or Word and it says I have the ctrl key pressed and asks if I want to go through. More commonly I don't get this warning, but inside Excel, the usual shortcuts ctrl-c ctrl-v, ctrl-o (new book, portuguese version) offer me the insert/delete rows dialog. Sometimes ctrl-ins has this behaviour too, other times it works fine while ctrl-c does not. It's all very random.Finally, to complete the problems described in the subject. I've also noticed a behavious I NEVER had before installing Win7. Most often while playing the MMO (but not exclusively there) my screen goes white with some activity going up and down (sort of a mis-tuned TV from the analogical days) and I can only bring it to place changing windows to get my normal desktop. The MMO runs in dedicated full-screen mode and I guess it must be changing resolution. Also frequently (about 40% of the times), when I boot my computer it shows up the wrong resolution (1024x768) and, in the login screen, the little button on the bottom-right that allows one to shut down and restart shows up only these two options when ordinarily it shows 4 to 6 options. During normal use, I often get the video-going-white problem when I tilt the laptop display up and down.In 3 years I never had one single of the symptoms with Vista, now I get them everyday. Problem is that I quite enjoyed Win7 (and I don't like Vista) so I'd like to keep this OS if possible.