800-1000 $ working PC work with after effect and photoshop

We can advise you about parts in a general way, but without knowing what is available to you it will be difficult.

I could link a company that ships internationally, but can they ship electronics to Iran? Would your budget include shipping costs?

look i think i can buy anything u advise me,but not from site u can just say it to me and i will go and buy it from comuter seller in my country ,cuz i dont have credit card to online buy i have to buy with bill ,so plz help me and just say what is best from 800-1000 $ just tel the parts tnx a lot again dude

OK, but I will leave some cushion in the budget in case your prices are higher.

Intel I5-750 CPU
Asus P55 motherboard P7P55D-E Pro
Kingston HyperX 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model KHX1600C8D3K2/4GX
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Antec Sonata case with 500W power supply
(must be this one. Do not decide to buy a cheap PSU. If this is not available see the PSU guide in my sig for a full list of good PSUs. The case is not so important but needs to have OK cooling.)
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Western Digital Caviar Black WD1002FAEX 1TB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive

Any major brand optical drive.

Windows 7 64-bit Premium OEM

EVGA 9500GT video card

ummmmm, get a spinpoint f3... not a caviar black

WD is usually more available and with a better warranty   Location means a bit more here.
Also, the Spinpoint is recommended for sustained reads... gaming.

The Seagate Constellation, if available, could be very nice for this sort of thing:
Seagate Constellation ES ST31000524NS 1TB

here is some testing:
http://www.xbitlabs.com/articles/storage/display/1tb-2t...
I thought this test especially applicable, but look around there are tons of tests in the article.