Hi,
I don't know much about computers, but I do find that surprising; some computers are left on for years for work or monitoring purposes, they might overheat or shut down sometimes or need a good clean. 24 hours x 8 months x 30 days is only 5760 hours... Strange to have such a short lifetime for a computer in sleep mode, but I'm unaware of what 'sleep' means for a computer, I rarely use it, maybe the computer is still using far more resources than the term 'sleep' or 'hibernate' suggests... Very hot where you live or something? Maybe the capacitors are low quality electrolytics? If you can identify them and check their datasheet, you might be able to see a reason for that having happened, possible even a specification with the expected lifetime in hours at such and such a temperature. Really wouldn't know what to suggest.