Listed below are the various steps to getting more games to work on your PC.
1. Use Optimization Software: Software such as TuneUp Utilities and Glary Utilities scan through your computer for stuff (other than viruses) which slow your computer down and fix these problems. Monthly usage of one of these programs can be really helpful.
TuneUp Utilities: 15-day Trial Version
Glary Utilities: Download Free
2. Use an antivirus software which supports "Silent/Gaming mode": Antivirus applications are often the reason why many games don't work on your system. Most modern antivirus applications support a special mode specifically for gaming and other resource intensive applications.
Example: Norton Internet Security (Download Here), Avast! Antivirus (Download Here)
3. Experiment with the quality of elements in-game: This is a surefire way to cure games that run slowly on your machine. Most games allow you to reduce or increase the quality of graphics, audio and gameplay to suit your machine. While reducing these factors is what almost always speeds up gaming, there are a few rare occasions where increasing the quality can make the game run faster.
4. Understand Compatibility & Windows related issues: There are some games which will never work on your computer, not because of a hardware shortcoming, but simply because your version of Windows does not support it. There are thousands of old games which no longer work because their publishers stopped developing patches for each new installment of the popular operating system. While a fair many of these "old" games can be run by changing the compatibility settings, others just will not work. Popular games, though, are often patched by the developer to support an advanced version of Windows.
Compatibility Settings can be changed in this manner:
1. Navigate to the folder where the game is installed via 'My Computer' (or Windows Explorer)
2. Right-click on the executable file of the game (which has a .exe extension/suffix), and click on 'Properties' from the list.
3. On the new window, select the 'Compatibility' tab. Feel free to change the options you find there.
5. Upgrade Wisely, Treat Your Hardware Well: When you do upgrade, upgrade to newly released products. Even if you may have to spend a few extra bucks, it will last you for much longer than an old product which you got cheap. This will save you money in the long run. Also, regularly clean your computer. A weekly dusting and monthly checking routine is imperative to having a solid performer.