[ubuntu] Secure boot questions/problems

I just discovered that my Virtualbox installation was broken, and tried to fix it. It's taken me several hours to get to where I can try to start virtual box but without the extension pack, it still won't work. To get to this point, I had to disable secure boot. I had a deadline last night that was compromised because virtualbox was broken - and these problems are threatening my education (and any hope I have for a future).

I'm using 14.04LTS and WILL NOT UPGRADE. The change from 12.04 to 14.04 took me weeks to figure out and get back to the way I wanted things (as well as getting all of the software I use to work) - admittedly that was on an old system and this one is new - a Dell preloaded with 8 which took me hours to kill (trashed 8 to where it wouldn't even start - and then I could boot from a Ubuntu CD). I am in the middle of the dissertation phase and cannot afford to have this system go down for days if not weeks, trying to get all of the different programs working again. So I'm staying with 14.04. I also can't have any more sudden crashes of software I regularly use! (Everything points to Secure Boot as being the problem.)

Question #1: Why Secure Boot?
Question #2: Why should I run it if I'm not doing dual boot or anything like that - and run widely different and esoteric software packages (specialized scientific analysis and amateur radio SDR for instance) that most people don't even have any use for - some of which is a few years old?
Question #3: How can I completely remove it - and still be secure when online or working? (I'm the only user on this computer.)

I run Virtualbox because I have some older Windows-only software that I run which isn't available under Linux (wXP, wXP SP3, W98, W95). Otherwise, I will never use Microsoft products again (unless forced as I am now). Thus, I should not have to deal with anything connected with that company. I won't be doing dual boot or ever using 10.