I'm responsible for few hundred high power Dell computers at work (although that is not my main job function). Most of the hardware issues in the past were due to hard drive failure not the main mother board. You're very lucky that it had lasted 5 years before it failed. However, inspect/clean the dust on the CPU and case cooling fan once every 6 months is a good practice.
30幾年來幾乎沒用過新電腦不是自己裝就是買舊貨甚至買壞的來修. There is nothing wrong using old computers.
