After applying thermal paste to CPU and GPU laptop won't boot

[Pokemonhan]

Hey guys,

I have a Dell XPS 15 L502X.

Specs:

Intel(R) Core(TM) i7-2670QM CPU @ 2.20 GHz
6 GB RAM
GeForce GT 525M
Samsung EVO 240 GB SSD (installed awhile back, was working perfectly fine)
Windows 8.1


Background: My screen was flashing on and off, switching between black screen and turning back on, each time saying the graphics card recovered. Looked at a few posts, nothing seemed to work. Tried looking at the cable, switching resolution, switching refresh rates but to no avail.

I then stumbled across a reply saying that it could potentially be due to the thermal paste on my CPU/GPU
http/www.tomsguide.com/answers/id-2016149/dell-xps-l502x-crash-issue.html

However, after reapplying and putting everything back together i get the following:

This product is covered by one or more of the following patents:
US5,307,459, US5,434,872 US5,732,094 US6,570,884 US6,115,776 US6,327,625
Realtek PCIe GBE Family Controller Series v2.37 (10/28/10)
PXE-E61 media test failure check cable

PXE-M0F Exiting PXE Rom

In addition to the above, whenever I turn my laptop on, the fan is spinning like crazy.

I don't quite understand what this means and any help would be appreciated!

Thank you

 

[anti-duck]

Go into BIOS and check your boot priority.

 

[Pokemonhan]

Go into BIOS and check your boot priority.

Went in, changed it to hard drive first, but it still returns the same thing unfortunately.

 

[anti-duck]

Is your hard drive being detected correctly in BIOS?

 

[Pokemonhan]

Is your hard drive being detected correctly in BIOS?

No it's not. Can't seem to detect any of my hard drives.

 

[anti-duck]

And have you tried your hard drive in other ports or in another computer if you have one? Are your SATA ports detecting your optical drive(s) if any?

 

[Pokemonhan]

And have you tried your hard drive in other ports or in another computer if you have one? Are your SATA ports detecting your optical drive(s) if any?

Just ran both hard drives on my computer and are working perfectly fine. I changed my optical drive and replaced it with a hard drive caddy, but it's unable to detect it.