After installing new graphics card the cpu keep restarting.

Cpu restarts in every 3 secs after installing new video card from asus. i have now intel video and its b...s..t with 128 mb memory on xp. interesting part is that shows 256 in 7. but still for playing games i need better card and my friend got me his old asus card with ati GPU:
EAX1300HM512/TD/128M more info: The ASUS EAX1300HM512 is equipped with ASUS exclusive innovations and ATI Radeon X1300LE GPU.

and for you about my cpu:

HP Compaq dc 7600
Intel Pentium 4 CPU 2.8 GHz
2048 MB Ram
Intel(R) 82945G Express Chipset Family video now
PCI-E slot for graphix

anyways if i take that card out everything works fine so i hope i can get my answer from here^^

HeKenZo welcome to the Seven Forums.

First thing to check is if this is the first video card ever installed, make sure that the slot is free from any dust/hair/etc. any debris in the slot can cause the card to not work.

Next which of the 3 different form factors that the model of Compaq came in is yours? Ultra slim, small form factor or mini-tower as all three came with a different power supply in them,

HP Compaq dc7600 Business PC - Worldwide QuickSpecs

If yours is the Ultra slim with the 200W power supply, that could also be the problem. The 240W in the small form factor probably isn't up to it either. The x1300 doesn't require much power, but HP is known for putting in a power supply that will just run what the computer came with, and makes it a crap shoot when adding any other hardware.

Unfortunately SFF based computers were not really designed for some upgrades, they were designed for basic computing. If your graphics card has a suggested power requirement, such as 300W or better, then you are basically not in a good position for your card. Also, SFF based computers aren't known for decent power supplies because it is meant for the bare minimum with minor add-ons, not nice beefy graphic cards, although you can try and see if they do have better power supplies, it will have to be through HP.

but where i can get that suggested power? asus site doesn't provide that kind a information:/i want to know how much that graphics card need

You should inquire with HP to see if there is a more powerful power supply available for your SFF... If not, your only other choice is to consider another card or another computer.