laptop wont boot

Guys ive tried for hours and i cannot get the lappy to boot ,
basically it froze and had to be shut down, upon rebooting this message comes up
Intel UNDI,pxe-2.1(build 082)
copyright (c) 1997-2000 intel corporation
For Atheros PCIE Ethernet controller v2.0.0.9(05/08/09)
check cable connection!
PXE-MOF ; Exiting intel PXE ROM.
No bootable device-- insert boot disk and press any key

i have tried to run startup repair but the operating sytem doesnt show, i cant find the sata drivers on the lenovo site ,so i cant load them.
im starting to panic as my partners college work is on it and is important .
the laptop is a lenovo G555 running win 7
thanks

Julian pal, it looks like it's trying to boot from LAN and not your HDD. Go into the bios and see if it detects your HDD. (It may just have lost the settings) Hopefully the HDD is ok. If it does detect you HDD change the settings to boot from your HDD first (you can disable the other boot devices if you want) ...

for the first time this evening i just got a message about boot manager it tells me an erroer occured whilst trying to read the boot configuration data. i kinda guessed that over the last 4 hours, anyhow its prompting me to run startup repair again so here goes,failing that i will try the bios i did look at it earlier and im pretty sure its set to run from HDD ,will post back in a few min

well it finally did something diffrent ,this time at start up repair it scanned for an operating system, it didnt do that before ,then i got an option to restart, i did and finally got the "windows did not shut down properly "message i should have got at 9 pm ,anyhow the exciting news is that i have my logon screen back ,now to see if all is well in lappy land. thanks for your imput guys, i have no idea why it has done this any suggestions welcome ,i would like to avoid this in future.

ok ,this is coming from the lenovo,the little bugger is behaving like nothing happened everything is as should be , i have a headache and missed my evening browsing .i think i mite make it play country and western songs all day tomorrow as a punishment, whilst i go out in the sun

no ,we have a cooling pad ,however this time it was left on a fabric footstool without the cooler by my partner so i shall mention it to her .do you think that it was overheating then .

Sounds like you had a heat problem.

Never, never, never set a laptop on you lap or on any fabric.

Most, but not all-apple being the smart one-have breathing vents on the bottom. Block those and the temps climb.

Two programs to monitor your temps: one is speccy, and another is CoreTemp. There are others but those are the two I use. I also install the coretemp gadget.

Check my sig for links.