At my new job, I have a production server with the following qualities:

• Windows (XP I think), ancient hardware
• Absolutely vital database
• No backups whatsoever
• Everyone in the company has full admin rights, the passwords are stored in a .txt on the global share
• No installers, except for the OS
• The machine itself is sitting on a wooden shelf 5 feet above the ground against an external wall with frequent truck traffic on the other side; the shelf is already bent from the constant load
• Hasn't been rebooted in $DEITY knows how long, my predecessor wasn't even sure if it would survive it
• UPS is installed, but since everything is hooked up to it, it would last 10 minutes tops
• No spare parts or hardware budget

How do I make a full backup with minimal impact on the server? I'm not sure how close it is to a total meltdown. For all I know, plugging in a USB stick could kill the company, and of course it will be all my fault, since "it was running fine before you touched it".

The ideal solution would be a VM, so I have a test environment as well (separate of course).