Constant freezes on my Computer!

If you believe you had done with optimization techniques and the problem still persist you might as well check the Hard-Drive healthiness because the HDD had life-span. You can check them using any free software which could provides S.M.A.R.T information on your hard drives. Because the lag and freezes can be happen because the I/O operation stopped because it's waiting for the hard-drive to response.

your computer is lack of maintenance. optimization can solve this problem. Do these steps and hangs can be reduced. You need some third party applications to achieve fast performance. check your hardware if they are working properly. go to run, then type msconfig in startup tab, uncheck the programs that you dont want to load during startup. clean your computer with ccleaner. it is a good utility for your computer. remove unnecessary files to your computer. also check your CPU usage, please kindly maintain your CPU usage below 90% to prevent reaching 100% CPU usage end unnecessary things in the task manager. but make sure you know that process you are ending before you end it. hopefully it helps..

My desktop pc had this problem, at times the entire screen used to become pink and flickered, after formatting it works fine now.

Check temperature of pc, maybe something is to hot and you have a protection. For example: temperature of CPU

how about try to clean your CPU or troubleshoot but for sure the dust is the reason why, like we let say the dust stopping your CPU fan to run correctly and because of that your CPU can't easily absorb the heat and by the time you CPU reach here heat level it will automatically turn off or restarted... but if not maybe your Hard Drive are almost full... if you playing games and got auto turn off or restarted maybe the requirement of the games you play are way to high from your computer specs, and by the time you defragmenting maybe some files are been corrupted about the scanning virus maybe your anti virus are already affected of the virus you already have and they can't scan it properly... try to scandisk and check thus two optional box after it done try to defrag and if it happen again maybe you need to reformat your computer

When was the last time you formatted.

What Operating system are you using ? if you are using Vista , then 1GB of ram is too little to support it.