How can I increase the FPS rate of my PC?

Let me give you my systems specs first:



OS: WinXP SP3

RAM : 1.50 GB

Remaining HDD Space: 70GB

Processor: Dual Core 2.80Ghz

Vcard: Nvidia GeForce 9400 512mb



Problem:

When I play games like LEFT 4 DEAD (SPECS: http://www.bigfatcheats.com/index.php?/Latest/Left-4-Dead-PC-Specs.html) and PROTOTYPE (SPECS: http://www.actiontrip.com/rei/comments_news.phtml?id=060109_5) my FPS rate is only at 5-7 (Checked it using FRAPS) so you can imagine how laggy/jumpy it is...



Things I tried doing so far:

- Reinstalled my OS

- Changed my screen refresh to 75Hz and turned on Vsync in Prototype (cant really notice the difference)

- Tried playing the game at its lowest possible settings (still very laggy)

- Updated the driver for the Vcard (there was a slight increase in FPS cause b4 I updated the driver FPS was at 2-3)

- Defragmented the HDD

- Closed prgrams and all background programs (like anti-virus) while playing the game (still didnt do much)



Additional Question:



I also notice that when I play in some websites flash videos (animefreak.tv) and play some Facebook flash games its also lagging badly, could these problems be connected? If so, how do I fix this?



I really need help with this, Ive been trying to figure this out for almost 2 weeks now..How can I increase the FPS rate of my PC?
You probably need to upgrade your PC. At the moment you are just running over minimum requirements, and I don't think Left 4 Dead will work perfectly on Windows XP to start with.



As these are fairly brand new games, they should work better on the other OS's Vista or 7.



Hope this helps!How can I increase the FPS rate of my PC?
One very importand step for performance is to download your motherboards chipset drivers.It affect acces to RAM dIisk drives etc.

If you have an NVIDIA chipset find the chipset series number and istall the drivers the same goes for all brands.Also if you can you may try some overclocking the CPU,there are many sites with instructions how to do it.
whatever you did will not improve the performance of your pc. here's what you need to do:



upgrade your ram to at least 4GB ddr2 pc800

increase the hard drive space to at least 320GB 10,000rpm

upgrade the processor to at least core 2 duo E8500 2.6 GHz, better if Q8400 2.66GHz

upgrade the GPU to nvidia 9800 1GB ddr2 at least

and try upgrading to windows 7 if possible because windows 7 runs faster than xp



PS: Never close the antivirus program