So, I went to my friends house today with my laptop (running Windows 7 Home Premium 64 bit) and it was working fine, but now when I've gone to log on at my house - it just hangs on the welcome screen once I enter my password and the hard drive activity light never goes out! At my friends house I only went on the internet on runescape (for the first time) and addictinggames.com; I have installed nothing since my last successful login.
I had noticed that for a while now Prevx, my virus checker, has been extremely slow analysing results and froze everything during the scan, but that's the only "sign" I've seen and neither Prevx nor MSE found any malicious software.
I have managed to gain access to a temporary account by pressing CTRL + Alt + Del and starting task manager and everything is painfully slow. My laptop has an i7 processor with 6 GB of RAM but at the minute, it may as well be a dinosaur of a machine.
Therefore, if anybody has any ideas or suggestions please post them. Similarly, if you require any additional information please don't hesitate to ask.
UPDATE: After a lot of hours of work, and some virus scanning, I find myself being logged into a "temporary profile". Virus scanning did uncover a few nasties but it appears that this is yet another Microsoft bug. I have found the following page, and it's pretty much about the exact same problem that I have: http://social.technet.microsoft.com/Forums/en/w7itprogeneral/thread/5ec0b949-effa-4e30-ba09-dc948a4c7a8b (Though I have a local account)
I've tried a couple of the most commonly suggested solutions but none of them have worked up to now. I will keep trying but if any one has experienced the same problem and/or knows of a solution, please try to assist me!
S.M.A.R.T Scan Results: As a few of you kept insisting that I should do a S.M.A.R.T scan on my new installation (see my answer) I installed SpeedFan. When I chose to "Perform an in-depth online analysis of this hard disk" everything shows up as "Very Good" or "Good" apart from the "Current pending sector" which it tells me to "Watch", as it looks "Critical". AND when I try to perfom an 'extended' or even a 'short' test it only gets so far before the status changes to "read failure". The performance bar is full, but the fitness bar is empty. However, I downloaded a couple more S.M.A.R.T scanners and both of them said everything was fine, including the "Current pending sector".
I did run ChkDsk built into Windows 7 but unfortunately I didn't see the results as I had to go out before it finished. Though, I did use "Active@ Hard Disk Monitor" to scan my disk and it found two bad blocks (of 128 sectors) but I do not know if the software tried to repair them, or marked them as unusable, etc... So, should I be worried about these results? I mean my system seems to running smoothly at the minute and at least I've got a backup set up now but I don't really want something like this happening to me unexpectedly...