Slow counter strike source running problem ?

These are my Computer Specifications :
Processor : Intel Pentium D 3.00 GHz
Motherboard : Intel D945GCCR
Video Card : Intel 82945G Express Chipset Family (128MB) with latest graphics driver
RAM : 1 GB
Hard Disk : 160 GB (152 GB usable) currently 59 GB used
Internet connection : ISP - TTML, Speed - 256 kB (as specified by ISP)
DirectX : 10
OS : Win XP SP2

My CS:S is running slow and sometimes i am getting message stating that Server Lost or Connection Problem. Is this happening because of slow Internet speed ???
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