hey games are really running slow and laggy graphics also sttuter?

Like owlwings stated, you need a good graphic card for games, not just the minimum requirements. And if you're a heavy gamer, often times the graphics & RAM will go first

Your PC probably needs 'tidying up'. Download and run CCleaner to get rid of unnecessary files and to remove unwanted entries in the registry; download and run Defraggler to defragment your hard disk. Both are free and can be downloaded from http://www.piriform.com/products

If your game was working fine before it means that something has changed and I'm wondering if you have other programs open that you don't normally use as these all use system resources. Also, just having the minimum system requirements is not enough. It's always best to upgrade your system to the maximum specifications that it can support in terms of memory and top of the range graphics card. I wish you luck. Andrew