I just bought the new components for my PC. They are;
- Asrock H61M-VS mainboard
- Intel i5 2500 CPU
- 2x4GB Transcend 1333
- WD Blue 750 GB HDD
- WD Green 1TB HDD
- Thermaltake TR2 RX 450W PSU
- Palit GT440 1GB
- LG IPS235V monitor
So, this is how it went.
1) I carefully installed all the components, made sure everything is in order, cables, fans, slots...connected the graphics card to monitor via DVI. Turned on the PC just to see if it all works - no signal. Bad start. Plugged out the DVI cable, took the D-Sub cable from the graphics card to monitor. Turned the PC on again - no signal. Then I've plugged the onboard D-Sub to my monitor and - finally some pictures. BIOS (UEFI) utility showed up, I checked the temperatures, saw everything was in order.
2) Then I've set the disk modes to AHCI, corrected the boot order (HDD #1 first, USB DVD second, HDD #2 off), plugged in the USB DVD drive, put the Windows 7 Ultimate disk, and started the installation procedure. Opted for the x64 version, made a 50GB partition just for the Windows, chose all the settings, typed the computer name and adjusted the date & time...then the installation showed "Preparing Your Desktop"...so I kept watching the nice blue background and waited...after 15 seconds, it flashed the desktop with all the icons and then - automatically showed "Logging Off" and "Shutting Down". After few seconds, the PC kept showing POST screen for a second, then nothing...and it looped. It went into some weird restart loop.
3) I repeated the process again, making sure I didn't make any mistakes. Installation got thru, "Preparing Your Desktop"....10 seconds after the glimpse of Windows desktop and the sudden "Logging Off" and "Shutting Down" screens. And the reboot loop again.
Tried to shut off the PC and turn it back on - it just kept rebooting around the POST screen.
4) Unplugged the second memory module and disconnected the backup HDD, leaving the PC with just one 4fGB module and one HDD. Tried the installation again. Same results.
5) Took the old XP SP2 disk, changed the disk modes to IDE, installed the XP SP2. Everything seemed to work normal.
6) Put the graphics card CD and tried to install the drivers, because I didnt want to work with the integrated graphics. NVidia installer alerted me that "there is no such hardware in your configuration". Checked the HW Monitor program, it displayed CPU, HDD and Mobo temps, but not the GPU temps. Checked the Device Manager under Display Adapter - only Intel graphics shown.
7) Took out the graphics card from the PC and tried to install Windows 7 again. Installation went thru and then the regular Preparing Your Desktop / Logging Off / POST screen reset loop.
Due to the number odd issues you are having, this sounds like a RAM problem. I've seen issues like this before and in every case it was a problem with the RAM. You said you took out the 2nd memory module. It's possible the stick you left in was actually the problem.
I'm gonna call out the psu as the culprit.
ATX2.2 power distribution is loaded up on the +3.3v and +5v not so much on the 12v =under 20A
New boards and gpus like lots of power from the 12v rails and your psu lacks that.
ATX12V 2.x PSUs have power distribution designed for late P4/XP PCs and for Athlon 64 and Core Duo PCs
Good psu for dual core =not good for quad core.
Try a better psu ATX 2.3 provide 20A minimum on the 12v rail and i bet your problems go away.