I don't think you can manually, i think you have to phone the Microsoft helpline. Hope this helped! :)
Be more specific repair on what but if its like RROD i suggest taking it to a repair shop
i think you can if you pay for it.
Microsoft did fix the RROD. It is still common for some Xbox's to have the RROD though.
Because I played the xbox too long and got the rrod.
with the new 65NM models its 99% that you will not get the RROD
You will probably need to send your Xbox in to Microsoft to get it repaired. You can look on the xbox.com website under support to see how to do this. You can always buy a Xbox Repair Guide too(Shows you how to fix your rrod yourself). You won't have to wait over six weeks until you get your Xbox back either. It's a lot cheaper and you could repair your 360 in under an hour. You can find a good repair guide for about $14. Link Below
It depends on wether or not it is still in warranty. If it's still in its 3 year RRoD warranty period, Microsoft will usually repair it for free, or send you a refurbished console. If its warranty period has expired, or if the warranty sticker has been removed or damaged, you will need to pay for a repair or refurbished console.
Because you have bought a used x-box 360 console and that's how you get the RROD
Yes. All Xbox 360 consoles are prone to overheating, which causes the RROD.
loose gpu or cpu
Yes
It depends what system you have silly:P if you don't own an Xbox, then RROD isn't an issue, likewise the otherway around, both of these are bad, and enable the system in-opperational,