Critical update led to black screen

I've got a big problem, hopefully someone will help me with the solution :) the other day, i got my hp pavilion dv7 notebook back from the workshop (it was there because of overheating). It worked perfectly for a day and a half, until a critical update from windows caused it to crash. After that, i only get to the user log in page, and when i enter to get to my desktop the screen turns black and the only thing i can see is the cursor. Task manager shows up when you ctrl alt del, but cant open, just says:"program couldn't start (0x0000022)". (sorry guys, for a messy post, im writing this on an iphone). I checked up a bit, but im a n00b, and using cmd in safe mode it seemed to be there is something wrong with cbs.log? "Windows resource protector found damaged files, but wasnt able to repair any of them. Details in CBS" or something like that. The first couple of days i was able to restore the system to an earlier point in time, and just keep the laptop on until the critical update forced itself on again. Now system restore gets me nowhere. The same as for restoring back to the fabricant. Wont work. Tried taking the battery in and out, holding the powerbutton for two minutes before putting the battery back in. Tried changing the screen resolution. Tried everything i can read online. I need your help! Ps i dont have the windows 7 cd

Without the install CD, or a restore partition there is nothing anyone can do for you. You will either have to buy a new copy of windows or see if you can get a copy of Linux to see if you can at least install an OS. You could attempt contacting HP to see if you can get a copy of the OS that came with your system. Good Luck