It is mostly a cost issue. If your computer is running fine and as fast as you would like it too, then there is no reason to buy another computer. Sometimes very simple things such as adding more ram will give you the boost that you desire.
If you bring your computer in to us we will look at it free of charge to see if an upgrade will be more beneficial to you then the purchase of a new computer. If the cost to upgrade reaches the cost of new then we will let you know that your machine is not cost effective to upgrade
Some reasons to upgrade your hardware over a new system is that you no longer have specialized programs that you need and cannot install it on a new system. Or maybe your software you use can only be run on older operating systems.
Microsoft allows a certain amount of upgrade before the operation system thinks it is on another computer and will make you purchase another license. If this happens a call to Microsoft will generally solve the problem
Most upgrades will not void your warranty. Some specialized computers are warrantied by your software vendor and they may void your warranty. Always check with them if that is the case.
You will get the manufactures warranty. If the part has a 3 year warranty that is what you will get. If we do the work to replace it and it goes bad while under warranty then we will send the part back for you and in some cases lend you another part so that you are not down on the computer. Your only charge will be a labor charge after 30 days.