well if i understood correctly,,,it started After your friend made a hole in the cabinet for you.(hopefuuly meaning you had it up and running before that already)now if so...
you can probably narrow it down to 2 things Hopefuuly.
1) while moving it around,,something has come loose in the back,,,hopefully,,easiest and simplest make sure all wires are snug where they belong,,mainly your power cord that goes into the power supply,,,mine was loose before and would shut off if i hit it with my leg.
(to check wires shut system off,before proceeding with them)
2)i would really check on your temperatures after checking your wires.
temperaturs should be no higher then 50 for your cpu,,above 50 and you will start to run into problems.
i have a simple 1.8 megabyte program that i install and uninstall from time to time.it is free trial for 14 days.it does not require anything.a download a setup..and it will appear on your desktop.click it your stuff(heat,fan rpm, and power supply) will be there being monitered.
here is the site incase you need to look into this further.
www.hmonitor.net/