Source games crash during load: Hl2, Counter Strike S., Garry's Mod...

Hi everybody :wave:

I'm having some trouble running any of these games:

Half Life 2, Counter Strike: Source, Garry's Mod. (And any other game with the Source engine)

Well, when each of these games load, when the background image isn't clear and there is a little message saying Loading on the right bottom corner, after some seconds loading it will crash with a memory error, which it didn't use to do before, but I have reallised that these errors are different in each of these games and also the RAM ussage raises to 95% and with out running any program my RAM ussage is 60-75%.
Here are the errors:
Half Life 2:
Memory error saying memory could not ''read''. I can't remember well this error, I will edit this post and add the proper errror.

Counter Strike: Source:
It will get to the actual menu, but with VERY VERY LOW fps, it will take 15 secs to open any option, and if I try joining any server, when it's loading an error will pop up:
Internal driver error in IDirect3DDevice9:resent()
Also I get a Xfire error:
<?xml version="1.0" encoding="utf-8" ?>

<ExceptionReport Version="4">
<Application Build="28504" Command=""d:\steam\steamapps\markyparky440\counter-strike source\hl2.exe" -steam -game cstrike "/>
<OperatingSystem Type="2"><Version Major="5" Minor="1" Build="2600"/></OperatingSystem>
<Exception Code="C000001D" Address="00300320"></Exception>
<Registers EAX="031FFCC0" EBX="0EB3A8B0" ECX="00000023" EDX="0BDF0840" ESI="0BDF0840" EDI="0EB5406C" CS="001B" EIP="00300320" SS="0023" ESP="0012FB98" EBP="00000000" DS="0023" ES="0023" FS="003B" GS="0000" Flags="00210286"/>
</ExceptionReport>

and

<?xml version="1.0" encoding="utf-8" ?>

<ExceptionReport Version="4">
<Application Build="28504" Command=""d:\steam\steamapps\markyparky440\counter-strike source\hl2.exe" -steam -game cstrike "/>
<OperatingSystem Type="2"><Version Major="5" Minor="1" Build="2600"/></OperatingSystem>
<Exception Code="C0000005" Address="0E97B423"><Module Section="0001" Offset="0000A423" FileName="d:\steam\steamapps\markyparky440\counter-strike source\bin\datacache.dll"/></Exception>
<Registers EAX="00000020" EBX="00000000" ECX="091FCA00" EDX="08206B00" ESI="0E98EA18" EDI="00000090" CS="001B" EIP="0E97B423" SS="0023" ESP="0012E6A0" EBP="00000002" DS="0023" ES="0023" FS="003B" GS="0000" Flags="00210202"/>
</ExceptionReport>


Garry's Mod:
It will do the same as Counter Strike: Source.

I have no checkpoints to restore system back to.
As I say, this didn't use to happen some months ago, so I'm not too sure why this is happening.

Here are my specs (I play on laptop):

Make: Asus
Model: z83j
CPU: Intel Centrino Duo T2400 (1.83Ghz)
Monitor: 17'' WXGA + (Came with laptop)
GPU/Graphics: Ati Mobility Radeon X1600 Pro - 512 MB
Ressolution: 1440 x 900 @ 60Hz
Wireless: 802.11a/b/g + BT (Wifi + Bluetooth)
Ram: 1GB
HDD: 250 GB
O.S: Windows Media Center 2005
Sound: Realtek HD Audio
Mouse: Logitech MX Revolution (''The most advanced mouse in the world'')
Keyboard: Logitech G15 (''Great for gaming, LCD pannel for better ingame communications'')
------------------------------------------------------
Temperatures (No coolers)
(Normal use, no games)

Core 0: 28 Cº
Core 1: 28 Cº
HD0: 33 Cº

(Ingame, Grand Theft Auto : San Andreas; Multi Theft Auto)

Core 0: 33Cº
Core 1: 33Cº
HD0: 35 Cº
------------------------------------------------------
Advanced

Motherboard:

Manufacturer: ASUSTek Computer Inc.
Model: A7J
Chipset: Intel i945PM
Southbridge: Intel 82801 GHM
LPCIO: ITE IT8705

BIOS:

Brand: American Megatrends Inc.
Version: 300
Date: 07/27/2006

Graphic Interface:

Version: PCI-Express
Link Width: x16
Max. Supported: x16

Memory:

General:

Type: DDR2
Channels #: Dual
Size: 1024 MBytes

Frequency: 332.5 MHz
FSBRAM: 1:2
CAS# Latency (tCL): 5.0 clocks
RAS# to CAS# Delay (tRCD): 5 clocks
RAS# Precharge (tRP): 5 clocks
Cycle Time (tRAS) 15 clocks
Bank Cycle Time (tRC) 5 clocks
------------------------------------------------------

Very detaied

Reguards,
Mark.