Was it my rooting that caused my Android to malfunction? Or what was it really?
It's pretty unlikely that rooting will ever cause hardware to malfunction--software maybe, but even then unlikely. 

In the event that you think a rooting process has caused your device software to malfunction it is advisable to attempt a full factory reset--since you had a hardware issue the device would still be malfunctioning. 

Edit: As Dan correctly notes below this is not the same as a 'Factory data reset' that you can find in the phone menu, it is more akin to flashing a stock rom including the recovery and often bootloader(and sometimes specialized software will be required). It looks like the device mentioned might be OEM by ZTE, maybe this thread would have a stock rom http://forum.xda-developers.com/showthread.php?t=1353526 )

One thing: It might be good to know what is actually happening with the root(maybe try to find a 'manual' root process) as some root procedures are more invasive/risky than others.