System failure while starting up!

[Adley]

Last night i had installed some new software on my PC, next day morning when i restarted my PC, the blue screen appears saying the Error. Then i again restarted the PC, and i got black window saying that,"INSERT DISK... PRESS ENTER. ".
Every time i boot up my computer i was getting the same Error message. Is there my harddrive randomly die? Yesterday my comp was doing well.. Then this happens. Is there a way by which I can fix this, i also thinking that yesterdays installation of software has corrupted the system files because of why it was not booting up, is there any way to recover the corrupted system files or am I going to have to buy a new HD and lose 120gb worth of data?

[Tweaker]

it may possible that you have lost your harddrive might have died. there is one chance where you can boot from a Windows disk and press R to repair from a prompt, then type chkdsk /r and press enter
let it run, it might work

[Benedict]

Ensure that your drives are empty
If there is a non bootable CD or disk in the drives, your computer might be attempting to boot the program with this disk. Hence, ensure that the floppy disk drive, the CD/R and DVD drives are all empty before restarting your computer and trying to run computer again.
that may be the reason why it was asking you to insert disk.

[Dodge]

Along with that also try out some following options:
BIOS set up
It might be linked to a wrong set up of BIOS. Hence,
To enter BIOS, press the F8 key when the Windows screen shows up upon the start of the computer.
Then all you have top do is to prioritize the boot sequence to Disk C:

If neither solution has solved your issue, then it might be due to a corruption of your system files. Therefore, Start your computer with a system boot CD and once it is running, enter the command “Dir C:” to ensure that you can access the C: drive’s contents.
If the computer enables you to access the contents, then you can enter the command
“fdisk /mbr
sys c:”

cheers