Need 400 W minimum PSU for this card. Also direct power connector for the card itself-- did you hook it up to the PSU ??
Specs below direct from ATI's website.

• PCI Express® based PC is required with one x16 lane graphics slot available on the motherboard
• Connection to the system power supply is required
• 400-Watt power supply or greater, 25 Amps, 12 volt rail recommended (assumes fully loaded system)
• For CrossFire™: 550 watt power supply or greater, 38 Amps, 12 volt rail
• 512MB of system memory
• Installation software requires CD-ROM drive
• DVD playback requires DVD drive and decoder software (not included)

hah haa! by god, ive got it. it works now. just needed to reseat it. but my motherboard works with the 300 W ih8bills. is that bad? gah alright, i got the thing to work, theres no problems, yet, but im sure there will be. thanks guys. mad monkey always comes through aayyyee. (:

Hey thanx Ray. It's never bad thing if your working. But if your working on 300w, you must be absolutely borderline. Adding an extra stick of RAM or something like that may push it over, but capacitor aging may also do that as well. Over time your PSU needs more power as they start to degrade. At the first signs, if not sooner, you start having problems booting up your PC, you'll know exactly what the problem is.

Glad you have it working...
Eventually, though being under-powered will catch up to you. Your power-suppy is the foundation of your system...
what happens to a building with a poor foundation ?

I recommend you budget for a new PSU ASAP.

go here and enter all your stuff for a good idea what you actually need... then add 50-100w for future upgrades

eXtreme Power Supply Calculator - What Power Supply Do I Need

i planned on getting a new one after christmas. i think my friend has a 500w he can sell me. so perhaps i shall jump on that.

if my psu isnt powerful enough, will it harm anything else like the mobo or video card?

holy **** i need a way bigger psu. : / i just did that little website dealy, and yea, i need a bigger one for sure.

Ijust put in ATI X1600, card itself needs a power cord

aside from the card slot