First check the internet to research understand the type of error that you have encountered. If you are unable to localize the error, or identify similar problems that other users have encountered, there are several things that you can do to try to fix the error instead.
This step may go without saying, but restarting a computer can often fix many problems that are in the registry or cache memory. Restarting a computer clears up a lot of temporary and junk data that is sitting around in your computers short term memory. Once you restart your computer, retry the application or process that was giving you a runtime error, and see if that clears it up. If not try shutting the computer down and letting it install any windows updates that may be available on shutdown. Often times, larger updates are only installed on shutdown and if they computer has not been shutdown in quite a while, the updates may be very important.
If the runtime error that you are encountering is relating to a newly installed application, you may want to try to reinstall the application fresh. Often, many runtime errors that occur with new applications are due to folder or files that are not installed correctly. Registry runtime errors can also fixed by uninstalling and reinstalling the program.
Check System Requirments
Many runtime errors occur when a computer does not meet the requirements of the system it is installed on. If you can have tried all other recommended fixes for the error, you may want to double check the system requirements and see if it could be related to any shortcomings of your computer. If your computer does not meet memory requirements or processor requirement, you can most likely attribute runtime errors to this.
Many runtime errors can be attributed to memory problems. In some cases these errors can be cleared up by shutting down tasks in the task manager. If there are too many high resource tasks being run the system may not have enough juice to run the applications that is being requested. Shutting these tasks down may provide a temporary fix, but it is a good sign that an upgrade is in order very soon.