Solved Auto login problems and strange behaviour

[ThisIsMadness91]

This morning, when switching on my PC, it hung on a black screen with the cursor visible for about half a minute after the "Starting Windows" screen. After that, I was prompted to enter my password, but I've had the "users must enter password" box unticked for over three years. I restarted in safe mode and was automatically logged in. I couldn't find the "users must enter password" box, but this was just because I wasn't looking closely enough. I restarted again and entered my password (probably a bad idea), and everything seemed normal. I found the "users must enter password" box, saw that it was unticked, restarted in safe mode and saw that this was still the case. I restarted again and changed my password.

After that, I restarted again and it loaded fine. I changed my password but noticed some strange differences. Programs seemed to take a bit longer to open than usual (Avira, Firefox, etc.), num lock was enabled by itself, and there were close to seventy processes running (when Windows has finished starting up, there are usually about sixty processes). I decided to restart and see if that solved the problem, but now I get an error message telling my the username or password is incorrect.

This has got me very worried and I'd appreciate any help you can provide. Also, what is the safest way to back up my files, the way that's least likely to back up any potential infections?

Update: My dad suggested disabling then re-enabling the automatic login. When I re-enabled it, I was asked to enter my new password (this was before restarting). I restarted and it logged in without any issue. The self-enabling num lock seems to have stopped as well, but the system still seems a bit slower than usual, and I'm not sure if the number of process after startup is normal or not. He's suggested either wiping my PC and starting over or getting a new one (either pre-built or custom). Before I make a decision, I'll wait and see if there's anything you guys think I should do.

 

[Layback Bear]

Well now so daddy said you could get another computer.
If daddy is paying it's a simple decision.
Build a brand new computer.
Put the old one away for a few week after getting the new one up and running.

When you drag out the old computer, tell daddy you are using it to learn and train on.

Give us a picture like this. We will start looking there.

 

[ThisIsMadness91]

Maybe I'm being too sensitive, but you're coming across as a bit condescending. I'll be paying for the new PC if I get one, but I'd rather not do that if there's nothing wrong with my current one, or if I can fix whatever may be wrong with it.

Here's the picture you asked for. I didn't have any programs like MBAM or Firefox open when I took it. The number of running processes looks about right now, and the system and programs seem to be going at the usual speed again. Still, better safe than sorry.

 

[ThisIsMadness91]

Sorry to bump this, but the login problem has returned. It's strange because it logged in automatically this morning, but when I switched the PC back on just now, it has gone back to starting up slowly (about 45 seconds of a black screen after the starting Windows screen) and asking me for my password.

Update: My dad suggested that I back up my files and do a clean install. Again, this seems like an extreme step to take, and I'd like to know what you guys think first. Also, I'd still like to know what file backup method is the least likely to backup any possible infections on my PC.

Really sorry to bother you all with this, but it's got me rather stressed out and I'm worried the whole thing's going to die on me before I can do anything to fix it.

 

[ThisIsMadness91]

Sorry for bumping again, but I installed a security update a week ago, and the start-up problem seems to have gone away since then. It could just be a coincidence, but I heard that the update for Patch Tuesday last month were causing problems for some people, and my problem started occurring not long after the updates were installed. I'll keep an eye on it for another week, and if I don't have any problems during that time, I'll mark the thread as solved.

Update: The problem hasn't come back since I made this last post, so I think everything's fixed.