My speed of gaming is very less. Can you tell me by what settings I could brig i

Firstly in the video/graphics settings in any game,
1. Start by reducing the Anti-aliasing and Anisotropic Filtering.
2. If that does not do it, reduce the shadow and particle effects a bit.
3. Yet, this still does not improve things reduce texture settings.
4. Not smooth enough, start lowering the resolution.

Hey, my gaming speed has been increased thanks but the cut scenes are not going correctly.When I had win xp, the videos was just wow but when my windows changed from xp to 7 videos are going in very bad quality, Please help me.

Please list out your computer specs. Processor, ram, graphics card, resolution... and then the game settings.

service pack 2
RAM-3.00 GB
Graphic card-NVIDEA GeForce 8400 GS
32 bit Operrating System
Processor-Pentinium [R] dual core CPU E2500@2.50GHz

Game settings-
Resolution-1024 X 768
Motion blur-On
Shadow Quality- High
Overall Quality-High
Framerate- Default
Anti Analising-off

There we go. Your set up is a really low end set up mate. Your 3GB RAM is why the speed is falling. Your processor is a low end processor. So is your graphics card.
You need more space, for starters. You have to increase your RAM.
If you can get a new processor and graphics card, go for it. But increase the RAM first. And lower the settings to medium, not high. High strains the comp and therefore lower speeds  

your gfx card wont play a lot of games its under spec for most newer 1s and some of the older 1s will just crash. if you are gonna play games on it you need to start with muinimum settings. putting any game thats younger than 3 years old on medium will just cripple your card...
i would suggest if you can that you get a replacement something low end like a gts240 or better.

Which game are you playing?

But when I had had windows xp, with these configuration and graphic card ang with game settings as I have told you, the game was going in very good quality.This problem started when I had changed windows xp to 7

Could you please state the game your playing ?  

Residnet Evil 5

is incompatible with the 8400gs... the game may start but will keep crashing...
all you can do is buy a better gfx card or stop trying to play the game.

So, tell me why it was not crashing in windows xp.

Best answer selected by Kumar Prayank.

Ok, Thanx