Now you've got 2 choices that I can think of.
1) On the off chance, take the HD round your mates house that also has evo and check on the C:/ drive to see if there is a folder called "backup", if its there it should contain a file called hdinfo.txt, which will tell you your hard drive unlock/lock code.
If you've got the hdinfo.txt file follow the guide here LINK
2) If you havn't got the hdinfo.txt file then you will need to buy LPC Mod chip so that you can get back into the drive. (if your freind has a matrix chip maybe he would lend it to you just long enough for you to re-lock the drive.