New graphics card, no monitor signal

[technoob4268]

Specs:

HP Pavilion Elite HPE-300z
Motherboard: H-RS880-uATX
PSU: 300W
PCI-E x16

Trying to replace ATI Radeon HD 5450 with XFX HD 6670

Things I've tried
- Attach DVI/VGA/HDMI cable to graphics card, not motherboard
- Update BIOS for primary to be PCI-E
- Remove/uninstall previous driver software/card
- Attach monitor to motherboard and let computer recognize new card or try to install new driver
- Remove power cord and hold start button for 1 min and reboot (read somewhere that this might work)
- The card does not have pins or require additional power source

Computer boots up fine (all lights running, hd running, fan on card is running) but there is no signal on monitor. Replaced old card back and works fine again, computer recognizes hardware and reinstalls drivers. I am aware that the recommended PSU is 400W but I've read several reviews where <300 have been sufficient.

I am not a smart tech person at all whatsoever, but googling and forum searches have taught me just a little bit. Please help. I have nowhere else to go.

Thank you.

 

[Fireman Dave]

Honestly, I would say it is your power supply =/ Not so much that it's only 300W, rather it's most likely a generic unit with rubbish 12V rail, sorry.

 

[technoob4268]

Honestly, I would say it is your power supply =/ Not so much that it's only 300W, rather it's most likely a generic unit with rubbish 12V rail, sorry.

alright man i appreciate the answer, ill look into upgrading the power supply