PC Maintenance
If overheating is not the problem see if you are keeping your computer clean from inside. By inside I mean the software. Many times we install various games, software, applications, just to try them out. But when we uninstall them some files created by these installations along with some registry entries are left behind. If such unused files occupy a large portion of your drive, your computer freezes frequently. To solve this install a registry cleaner and clean up your windows registry from time to time. Also, defragment the drive and run the disk clean up utility.
Virus Check
If you have checked your computer for overheating and you have cleaned up your registry and defragmented your computer but still your computer keeps freezing, the problem might be a computer virus attack. Certain viruses like the trojan horse, can slow down your computer tremendously. If you spend a lot of time on the web an antivirus is mandatory for your computer. There are many free antivirus software available, which you can use to keep your computer virus free. But you have to update them regularly.
Computer Memory Check
Your computer needs hard drive space to operate. So sometimes your PC keeps freezing randomly due to lack of hard drive space. Also, if your RAM is less your computer will use the hard drive space as virtual memory. But if that is also not available, your computer keeps freezing up. The solution to this problem is pretty straight forward. Upgrade your RAM and hard drive. Also, if you are using an advanced operating system see if your computer configuration matches it.
Update All the Software
Updating all software including the operating system from time to time is also very important to ensure good computer performance. Especially antivirus software which has to be updated almost daily. Updating them ensures that all the bugs in them are removed.