It's what we all dread - turning on the computer, and finding it refuses to boot. One week ago tomorrow, it happened to me. My computer has not been declared dead quite yet, but it's been in the shop for 6 days, and they are still trying to resuscitate it. Thank goodness I have my laptop as a backup, as well as my smart phone, but in this last week I've been glad for some of the preemptive things I've done, and I've learned some lessons on other things I should have done better to prepare for this.
My words of wisdom -
First and foremost, back up your data! I use Carbonite (no connection, no relationship to declare) but there are numerous services out there. One thing to be cautious of - some unlimited automatic backup services allow you a certain amount of data, and after you have reached that limit, they throttle your backup speeds. This has been an issue with my service in the past, and I understand that they no longer to this; but prior to the change, I would find files I had created weeks prior had still not been backed up. Check your backup periodically to see just how fast your files are being uploaded. Carbonite has a "control center" that tells you how many files are pending at any given time, and also identifies them by name.
In addition, check various file types to make sure they're being backed up. By default, my service does not back up movie files (as well as others), so I had to be certain that all those file types were included in the uploads.
Second, do local backups. Huge external drives are relatively cheap; so much so that I have two of them connected to my computer, one set to back up every Saturday night, and the other every Wednesday night (patting myself on the back for that). Unfortunately, in the month or so prior to my computer failure, I had unplugged the drives for some reason that escapes me now, and I don't recall ever plugging them back in (kicking myself firmly in the backside for that). The moral of the story is this: just because you haven't had a computer failure in the past doesn't mean it's not coming, so take it very seriously, as if it was just around the corner. It might be!
Third, go ahead and have your browser save your passwords, if you wish. It's convenient. But remember that even though you might have access to another computer, that computer will not help you with all those passwords. I have no experience with password managers, and in this day and age of abundant hacking, I am not sure I want all my passwords in one place. Thank goodness, I keep a recipe card file with my passwords managed the old fashioned way - one card for each website/account, and filed in alphabetical order. Though it's occasionally been a real pain to make a written note of my passwords, and to update the file every time I've changed a password, it's something I am really, really glad I did now.
Fourth, if you haven't already made that emergency boot disk, take a few minutes and do it now. Also, if your antivirus program has instructions for making a boot disk, do that as well. If you have a virus that makes your computer inoperable, having virus definitions easily at hand could be huge in recovering your data. In my particular case, my boot disk did not help, but had the circumstances been different, I could have backed up those new photos of the grandkids that I'd just unloaded from the camera, instead of hoping Carbonite was fast enough to upload them. And I could potentially have fixed the problem myself instead of having to pay someone else to do it.
Hopefully in the next day or two, I'll have my computer back, complete with a new and improved hard drive, and all my data intact. Hopefully.