New build - no monitor signal

[Josh52]

Hi, I recently built a new gaming computer with these specs:
AMD Phenom II BE
MSI 870A-G54 mobo
Geforce GTX 550-ti
8gb XMS-3 corsair RAM (twox4gb)
Modxstream pro PSU

I've assembled it and it seems to be working, but when I plug it into a monitor through the DVI ports on the graphics card, the monitor gives the 'no signal input' message. I've tried both DVI ports, the HDMI port and tried it in several different monitors with the same effect. I can't try it through the motherboard, as that series has no integrated graphics and so no way to connect to a monitor.
Any suggestions?
Thanks in advance for the advice.

 

[jsc]

Look at this:
http://www.tomshardware.co.uk/forum/274745-13-step-step-guide-building
to make sure you didn't overlook someting simple.

Then work systematically through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

 

[Josh52]

I've experienced problems with this machine before (a faulty PSU) and so have already worked through that list more than once, except for using a system speaker. I was hoping there might be another solution before I bought one. The fans on the GPU and CPU work, but the components themselves could be faulty...
Thanks for the quick reply.