In a small percentage of all cases, the equipment will fail shortly after you've installed it. This is almost always due to a small problem with the final assembly, but sometimes the equipment does have a defect. Generally, the store you bought it from will fix a problem and replace a defective component very quickly. In some cases, the equipment will fail during the first couple of years. This is relatively rare, but it does happen.
Most problems come from incompatibilities between software and buggy drivers.
Systems have a tendency to become more and more unstable as software is installed and removed from them. Also, people tend to turn off their computers without shutting them down properly. As programs start to crash, you're forced to turn off the power more often without shutting down properly. Even the big manufacturers have problems making sure that they're getting current RAM from a licensed distributor. Check the manufacturers date code, if you can find one.