Should I update my old computer or buy a new one?

Tweet

I want to update my computer but there are many tings in my mind when I go for it then some confusion in my mind because now my computer is 5 years old. And when I purchased it then its cost was 26000 rupees. And that time configuration was 80 GB of Hard Disk, 256 MB of DDR RAM, DVD writer, Gigabyte Mother Board, Creative 2 in 1 Speaker with subwoofer and 17” Monitor. But now time has changed and I need more capacity of hard disk. And also I want to update its RAM up to 1 GB. And when I inquired for DDR RAM of 1 GB and about 500 GB Hard disk then its cost around 3600. Yes both products are available in 3600 rupees. And now I am in confusion because now I should only update some part of old computer or should buy a new one. Please give me suggestion.