Try a PRAM Reset (hold for at least three chimes) to see if that allows you to boot back into Recovery Mode. Those hacks modify the PRAM settings to allow a customized boot for the hack. Remove those custom PRAM settings & the computer should behave normally....at least for booting from DVD or a USB stick (no idea about Recovery Mode since I don't know what you changed....was it to the virtual image you have highlighted or the one on the internal HD?....the latter would be bad news).
What is the exact model of your laptop? You can try entering the system serial number on the check coverage page here (don't post the serial# on the forum since it is considered personal information):
View Coverage - AppleCare & Warranty
If the check coverage page doesn't provide the exact model, then is your laptop a 32 bit only Core Duo CPU or a 64bit Core 2 Duo CPU? You may be able to retrieve that information from the sticker inside the battery bay.