Corrupt Registry Issue

Please Assist if possible...

I have made some changes in the registry. I have added an autokillvalue key through making a notepad file and merging it. I have also enabled maximum Ram for start-up (in Msconfig). I then updated windows with about 10 normal updates and 1 optional then restarted the laptop. On starting up, 'Bad system config' message is displayed and windows is therefore unable to start.

Windows now does not start. It instead goes through to system repair and unsuprisingly that does not work neither does lasy known working config, safe mode or system restore. I have also ran a memory test.

In startup repair, the problem details are below:

Problem Event Name: StartupRepairOffline
Problem Signature 01: 6.1.7600.16.385
Problem Signature 02: 6.1 7600.16.385
Problem Signature 03: unknown
Problem Signature 04: 21200359
Problem Signature 05: AutoFailover
Problem Signature 06: 12
Problem Signature 07: Corrupt Registry
OS Version: 6.1.7600.2.0.0.256.1

I am quite sure this is due to my fiddling with the registry. Whilst I am confident it isnt the changes I made per se, I think it is to do with the merge to the registry I made. I wondered if using reg.exe to remove autokillservice might work but don't know the command line and don't want to try this as I dont have a clue about reg.exe.

WIN 7 home. Sony Vaio Laptop.

Please Advise....

Thanks!