I have an hp computer that I had a PC repair store do some work on. They wiped it clean (giving it to a friend) & since then it has been sitting in a corner. Decided to plug it all in & make sure everything was there before sending it off. I now have an error message "disk boot failure, insert system disk and press enter". I ALSO can't get the CD/DVD drive to open. I even tried to do it manually with a paperclip. The green light comes on & you can hear it trying, but nothing opens/comes out....could these 2 things be related? How do i get the drive to open when I can't even get passed the main screen?
Here is the CD Eject Tool.
You must open the CD tray and insert the Windows CD before the boot up starts.
http://www.lancelhoff.com/disk-boot-failure-insert-system-disk-and-press-enter/
The FIRST suggestion in this link worked out for me before. Good morning turkeyheath

Just like the link jason2074 posted may help you, and also the paperclip trick that Geek-9PM shows works GREAT for ejecting a disk when the cd drive will not open plus you can do this in windows if you go into "my computer" and look for your cd drive letter (ie "D" or "E") and right click that drive and select "eject" this to may work sometimes so long as the drive is not stuck to bad.

Things to look at but please remember to try these only when the PC is off and for extra protection unplug your power cord from the power supply in the back of your PC

Open the desktop up by removing the side case panel and look inside if the PC is a little older the Hard drive and CD drives may have IDE cables and a power plug (molex connector) the molex plug can only fit in one way so that part is straight forward. Now the IDE should ALWAYS have a red stripe that stripe (or red dashes) has to be facing the power plug  you may want to check these.

Now to check the jumpers on the CD drives and hard drives depending on how old the PC is the drive manufacture may PREFER to use the master / slave setting or cable select but to give you an idea what the jumpers look like    

The reason I am putting this in here is the jumper settings may be the issue.

Also if you have IDE drives (hard drive and cd drive) say one of each they must be connected to the last connector on the IDE cable here is a pic to show that

Now if your PC has sata cables there is no master / slave connection only one drive can be connected to a sata cable at a time.
here is a sata cable

some sata cable have a power plug and data plug together like this

The big thing to keep in mind ALL sata cables can only be plugged in one way and with to much pressure can brake off the tab on the drive here is what the sata ports look like on the hard drive

If all connections are correct on all drives, check and make sure there is no floppy disk in the drive, no usb thumb drives plugged in and double check the boot sequence in the BIOS, one last thing if there is a multi-card reader either plugged into the header plug on the motherboard or a usb card reader plugged into the usb port on some systems can stop a PC from boot. But his only HAPPENS on few PC systems.

If nothing seems to work the OS may need to be re-installed or you may have a bad drive. 

Please let us know how you make out, i am curious to see what your issue was.