Monitor receives NO SIGNAL after moving computer/changing resolution; I've tried all suggestions on the internet to no avail!

[chosenhobo]

Specs

Computer: Dell XPS 420

• 
  OS: Windows Vista (Not sure 32-bit or 64-bit)
  Motherboard: Dell BTX motherboard
  CPU: 2.4GHz Intel Core 2 Quad Q6600
  RAM: 2GB (not sure)
  Graphics: GeForce 8800 GTX

Monitor: ASUS VS278Q-P

Story: Been missing having a nice old desktop since college has shifted me to use primarily laptops, so decided to move my old PC from home to my apartment.

1. PC was working previously at home with no issues.
2. Monitor (ASUS VS278Q-P) newly purchased a few days ago.
3. When I first hooked up the PC to the Monitor, it worked, but resolution was UGLY. So I changed it.

• 
  - When I first connected it to the monitor, it had been defaulted to 1024x600.
  - I changed the resolution to 1366x768. For some reason the PC did not display the option for 1920x1080, the monitor's native resolution.

4. After changing resolution, I figured I wanted to reformat the computer since it had years of junk on it anyways. After I turned it off, that's when the computer no longer outputs signal to monitor.
5. Because of 4, I can not see/access Safe Mode (F8), BIOS (F2), or Alternative Boot (F12)

I have searched online endlessly for the past 2 days, and I've been trying everything that everyone has been suggesting:

• 
  - Reset CMOS. Have both pulled battery and used CMOS jumper.
  - Took out RAM to see if motherboard beeps upon startup. (Yes)
  - Reseated all components.
  - Unplugged computer, pushed power button for 5 minutes (power cycling)
  - Unplugged all components except for CPU, RAM, HD, Video Card

I'm getting pretty frustrated at this point, and don't know what else to do. I feel like it shouldn't be a hardware issue, since it literally worked when I first tried it, then stopped working 15 minutes later. I don't really want to buy another computer, I bought my monitor because I figured, "Hey, I have a pretty decent computer back home which I can use to just do my school programming and stuff.", NOT because I want to have a gaming rig or anything.

Other information:

• 
  - Monitor works flawlessly when connecting my laptops.
  - PC has no mobo onboard-display port
  - Connecting PC to monitor in this fashion: PC(only has 2 DVI ports)->DVI-HDMI Adapter->Monitor(HDMI port)[Only has HDMI, Displayport, and VGA)
  - All fans in computer spinning, components seem to run.
  - When pressing F8 for Safe Mode, there's no signal on the monitor still, but I do suddenly hear a bunch of beeping if I hold down F8. I searched online, and found this may just be "buffer overflow", but idk..

I have tried everything in the thread "PERFORM THESE STEPS before posting about POST/boot/no video problems!" aside form those that include trying other parts, since I don't have any and don't have money.
Any other suggestions??

 

[knight_of_baawa]

Is there onboard video? If so--try that.

 

[chosenhobo]

Is there onboard video? If so--try that.

Unfortunately, there isn't..

 

[knight_of_baawa]

Well, other than what you don't want to hear (part replacement to check for what it could be), there's no other option.