Isn't [tag:computer] a meta-tag?  
And I imagine [tag:PC] is perilously close to being one as well...

For the same reasons as discussed over in https://meta.superuser.com/questions/2017/can-the-hardware-and-software-tags-be-obliterated

Surely *every* question on SU should be related to computers (as per the FAQ), and therefore every question should use this tag... looks very meta to me.