Resolution Issue, please help!

[Romboldt]

Hopefully you guys can help me, I'm having resolution issues, my guest OS is stuck maxed out at 800x600, which makes it nearly impossible for me to work on it. I posted similar in a thread from a few years ago, not realizing how old/dead it was, so I've reposted a fresh thread. I've already tried a lot of troubleshooting with no success, so let me summarize my problem and my attempts at troubleshooting thus far:

I'm using a Windows 7 Home Premium host.
I'm running an OS designed by my employer as a guest. It seems to have 3-5 different OSes floating around in there for some bizarre reason, but at its core seems to be linux or ubuntu. Pardon my ignorance, my experience with OSes is limited. ^_^;

Unfortunately because it's a work OS, I have no administrator priveledges on the guest OS, which long story short makes Guest Additions a no-go. I've tried literally everything conceivable and I cannot get it to install.

With that said I've tried changing settings host-side to try to correct the issue. I've come across the "vboxmanage setextradata" etc etc commands (and there seem to be an alarming number of variations) but none of them have any sort of effect. I've tried different resolutions, varied commands, and tried with/without the guest running as well as performing restarts. Nothing seems to work.

I also noticed the command posted by Snake, but don't quite understand how to use it. I'm assuming it's intended to be run from the guest OS terminal? I tried this and it didn't work. "No such file or directory"

Please help! T.T