Video Card Problems

Recently I upgraded my video card to Radeon 9600XT. Ever since then after powering down my computer and restarting it, the video is scrambled right from the post to the windows start up screen. Rebooting seems to fix the problem until the machine is restarted. I’ve checked all my settings and they seem to be correct. I’ve also reformatted and reloaded windows but it didn’t help. Any ideas on how to fix this problem. My computers specs are
2.8GHZ intel processor
512MB of PC3200 DDR Memory
450W Powermax power supply
80gig maxtor hard drive
Soundblaster Live 5.1 sound card
Gigabyte 8IEP1000 Pro 3 Motherboard.

Any answers you could provide would be appreciated. Thanks.