While i love uniq, it's not a solution here. OP said "I want to remove duplicate entries for one single instance of COMPUTER column." Not eliminate duplicate lines, which your uniq examples doe.

My first action after reading OP was to man uniq -- there's options to "avoid comparing the first N fields" and "avoid comparing the first N characters", but unfortunately neither of those work for comparing just the first column (of a tab-delim'd file).