How much is my computer worth?

depends, if you are selling to someone who knows about computers then about 500-800, if you are selling to some fool who doesn't then 1500-2000 just cause they are stupid. with roughly the same specs as yours, with a quad core i5 2.8ghz, a gigabyte OC 6970 with 2g DDR5, a cooler master 700W PSU, and a coolermaster sniper black full tower and mine cost me $900 to build, so if i was selling mine to a person with brains they should only pay about a 1000. but in reality someone would probably pay 1500 for yours.